switch to vuepress

2 files changed, 1563 insertions, 0 deletions

diff --git a/node_modules/isemail/lib/index.d.ts b/node_modules/isemail/lib/index.d.ts
new file mode 100644
index 00000000..2ece3854
--- /dev/null
+++ b/node_modules/isemail/lib/index.d.ts
@@ -0,0 +1,64 @@
+// Code shows a string is valid,
+// but docs require string array or object.
+type TLDList = string | string[] | { [topLevelDomain: string]: any };
+
+type BaseOptions = {
+  tldWhitelist?: TLDList;
+  tldBlacklist?: TLDList;
+  minDomainAtoms?: number;
+  allowUnicode?: boolean;
+};
+
+type OptionsWithBool = BaseOptions & {
+  errorLevel?: false;
+};
+
+type OptionsWithNumThreshold = BaseOptions & {
+  errorLevel?: true | number;
+};
+
+interface Validator {
+  /**
+   * Check that an email address conforms to RFCs 5321, 5322, 6530 and others.
+   *
+   *  ```
+   * import * as IsEmail from "isemail";
+   *
+   * IsEmail.validate("test@e.com");
+   * // => true
+   * ```
+   */
+  validate(email: string): boolean;
+
+  /**
+   * Check that an email address conforms to RFCs 5321, 5322, 6530 and others.
+   *
+   * ```
+   * import * as IsEmail from "isemail";
+   *
+   * IsEmail.validate("test@iana.org", { errorLevel: false });
+   * // => true
+   * ```
+   */
+  validate(email: string, options: OptionsWithBool): boolean;
+
+  /**
+   * Check that an email address conforms to RFCs 5321, 5322, 6530 and others.
+   *
+   * ```
+   * import * as IsEmail from "isemail";
+   *
+   * IsEmail.validate("test@iana.org", { errorLevel: true });
+   * // => 0
+   * IsEmail.validate("test @e.com", { errorLevel: 50 });
+   * // => 0
+   * IsEmail.validate('test @e.com', { errorLevel: true })
+   * // => 49
+   * ```
+   */
+  validate(email: string, options: OptionsWithNumThreshold): number;
+}
+
+declare const IsEmail: Validator;
+
+export = IsEmail;
diff --git a/node_modules/isemail/lib/index.js b/node_modules/isemail/lib/index.js
new file mode 100644
index 00000000..4f3d4cc3
--- /dev/null
+++ b/node_modules/isemail/lib/index.js
@@ -0,0 +1,1499 @@
+'use strict';
+
+// Load modules
+
+const Punycode = require('punycode');
+const Util = require('util');
+
+// Declare internals
+
+const internals = {
+    hasOwn: Object.prototype.hasOwnProperty,
+    indexOf: Array.prototype.indexOf,
+    defaultThreshold: 16,
+    maxIPv6Groups: 8,
+
+    categories: {
+        valid: 1,
+        dnsWarn: 7,
+        rfc5321: 15,
+        cfws: 31,
+        deprecated: 63,
+        rfc5322: 127,
+        error: 255
+    },
+
+    diagnoses: {
+
+        // Address is valid
+
+        valid: 0,
+
+        // Address is valid for SMTP but has unusual elements
+
+        rfc5321TLD: 9,
+        rfc5321TLDNumeric: 10,
+        rfc5321QuotedString: 11,
+        rfc5321AddressLiteral: 12,
+
+        // Address is valid for message, but must be modified for envelope
+
+        cfwsComment: 17,
+        cfwsFWS: 18,
+
+        // Address contains non-ASCII when the allowUnicode option is false
+        // Has to be > internals.defaultThreshold so that it's rejected
+        // without an explicit errorLevel:
+        undesiredNonAscii: 25,
+
+        // Address contains deprecated elements, but may still be valid in some contexts
+
+        deprecatedLocalPart: 33,
+        deprecatedFWS: 34,
+        deprecatedQTEXT: 35,
+        deprecatedQP: 36,
+        deprecatedComment: 37,
+        deprecatedCTEXT: 38,
+        deprecatedIPv6: 39,
+        deprecatedCFWSNearAt: 49,
+
+        // Address is only valid according to broad definition in RFC 5322, but is otherwise invalid
+
+        rfc5322Domain: 65,
+        rfc5322TooLong: 66,
+        rfc5322LocalTooLong: 67,
+        rfc5322DomainTooLong: 68,
+        rfc5322LabelTooLong: 69,
+        rfc5322DomainLiteral: 70,
+        rfc5322DomainLiteralOBSDText: 71,
+        rfc5322IPv6GroupCount: 72,
+        rfc5322IPv62x2xColon: 73,
+        rfc5322IPv6BadCharacter: 74,
+        rfc5322IPv6MaxGroups: 75,
+        rfc5322IPv6ColonStart: 76,
+        rfc5322IPv6ColonEnd: 77,
+
+        // Address is invalid for any purpose
+
+        errExpectingDTEXT: 129,
+        errNoLocalPart: 130,
+        errNoDomain: 131,
+        errConsecutiveDots: 132,
+        errATEXTAfterCFWS: 133,
+        errATEXTAfterQS: 134,
+        errATEXTAfterDomainLiteral: 135,
+        errExpectingQPair: 136,
+        errExpectingATEXT: 137,
+        errExpectingQTEXT: 138,
+        errExpectingCTEXT: 139,
+        errBackslashEnd: 140,
+        errDotStart: 141,
+        errDotEnd: 142,
+        errDomainHyphenStart: 143,
+        errDomainHyphenEnd: 144,
+        errUnclosedQuotedString: 145,
+        errUnclosedComment: 146,
+        errUnclosedDomainLiteral: 147,
+        errFWSCRLFx2: 148,
+        errFWSCRLFEnd: 149,
+        errCRNoLF: 150,
+        errUnknownTLD: 160,
+        errDomainTooShort: 161,
+        errDotAfterDomainLiteral: 162
+    },
+
+    components: {
+        localpart: 0,
+        domain: 1,
+        literal: 2,
+        contextComment: 3,
+        contextFWS: 4,
+        contextQuotedString: 5,
+        contextQuotedPair: 6
+    }
+};
+
+
+internals.specials = function () {
+
+    const specials = '()<>[]:;@\\,."';        // US-ASCII visible characters not valid for atext (http://tools.ietf.org/html/rfc5322#section-3.2.3)
+    const lookup = new Array(0x100);
+    lookup.fill(false);
+
+    for (let i = 0; i < specials.length; ++i) {
+        lookup[specials.codePointAt(i)] = true;
+    }
+
+    return function (code) {
+
+        return lookup[code];
+    };
+}();
+
+internals.c0Controls = function () {
+
+    const lookup = new Array(0x100);
+    lookup.fill(false);
+
+    // add C0 control characters
+
+    for (let i = 0; i < 33; ++i) {
+        lookup[i] = true;
+    }
+
+    return function (code) {
+
+        return lookup[code];
+    };
+}();
+
+internals.c1Controls = function () {
+
+    const lookup = new Array(0x100);
+    lookup.fill(false);
+
+    // add C1 control characters
+
+    for (let i = 127; i < 160; ++i) {
+        lookup[i] = true;
+    }
+
+    return function (code) {
+
+        return lookup[code];
+    };
+}();
+
+internals.regex = {
+    ipV4: /\b(?:(?:25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(?:25[0-5]|2[0-4]\d|[01]?\d\d?)$/,
+    ipV6: /^[a-fA-F\d]{0,4}$/
+};
+
+internals.normalizeSupportsNul = '\0'.normalize('NFC') === '\0';
+
+
+// $lab:coverage:off$
+internals.nulNormalize = function (email) {
+
+    return email.split('\0').map((part) => part.normalize('NFC')).join('\0');
+};
+// $lab:coverage:on$
+
+
+internals.normalize = function (email) {
+
+    return email.normalize('NFC');
+};
+
+
+// $lab:coverage:off$
+if (!internals.normalizeSupportsNul) {
+    internals.normalize = function (email) {
+
+        if (email.indexOf('\0') >= 0) {
+            return internals.nulNormalize(email);
+        }
+
+        return email.normalize('NFC');
+    };
+}
+// $lab:coverage:on$
+
+
+internals.checkIpV6 = function (items) {
+
+    return items.every((value) => internals.regex.ipV6.test(value));
+};
+
+
+internals.isIterable = Array.isArray;
+
+
+/* $lab:coverage:off$ */
+if (typeof Symbol !== 'undefined') {
+    internals.isIterable = (value) => Array.isArray(value) || (!!value && typeof value === 'object' && typeof value[Symbol.iterator] === 'function');
+}
+/* $lab:coverage:on$ */
+
+
+// Node 10 introduced isSet and isMap, which are useful for cross-context type
+// checking.
+// $lab:coverage:off$
+internals._isSet = (value) => value instanceof Set;
+internals._isMap = (value) => value instanceof Map;
+internals.isSet = Util.types && Util.types.isSet || internals._isSet;
+internals.isMap = Util.types && Util.types.isMap || internals._isMap;
+// $lab:coverage:on$
+
+
+/**
+ * Normalize the given lookup "table" to an iterator. Outputs items in arrays
+ * and sets, keys from maps (regardless of the corresponding value), and own
+ * enumerable keys from all other objects (intended to be plain objects).
+ *
+ * @param {*} table The table to convert.
+ * @returns {Iterable<*>} The converted table.
+ */
+internals.normalizeTable = function (table) {
+
+    if (internals.isSet(table) || Array.isArray(table)) {
+        return table;
+    }
+
+    if (internals.isMap(table)) {
+        return table.keys();
+    }
+
+    return Object.keys(table);
+};
+
+
+/**
+ * Convert the given domain atom to its canonical form using Nameprep and string
+ * lowercasing. Domain atoms that are all-ASCII will not undergo any changes via
+ * Nameprep, and domain atoms that have already been canonicalized will not be
+ * altered.
+ *
+ * @param {string} atom The atom to canonicalize.
+ * @returns {string} The canonicalized atom.
+ */
+internals.canonicalizeAtom = function (atom) {
+
+    return Punycode.toASCII(atom).toLowerCase();
+};
+
+
+/**
+ * Check whether any of the values in the given iterable, when passed through
+ * the iteratee function, are equal to the given value.
+ *
+ * @param {Iterable<*>} iterable The iterable to check.
+ * @param {function(*): *} iteratee The iteratee that receives each item from
+ *   the iterable.
+ * @param {*} value The reference value.
+ * @returns {boolean} Whether the given value matches any of the items in the
+ *   iterable per the iteratee.
+ */
+internals.includesMapped = function (iterable, iteratee, value) {
+
+    for (const item of iterable) {
+        if (value === iteratee(item)) {
+            return true;
+        }
+    }
+
+    return false;
+};
+
+
+/**
+ * Check whether the given top-level domain atom is valid based on the
+ * configured blacklist/whitelist.
+ *
+ * @param {string} tldAtom The atom to check.
+ * @param {Object} options
+ *   {*} tldBlacklist The set of domains to consider invalid.
+ *   {*} tldWhitelist The set of domains to consider valid.
+ * @returns {boolean} Whether the given domain atom is valid per the blacklist/
+ *   whitelist.
+ */
+internals.validDomain = function (tldAtom, options) {
+
+    // Nameprep handles case-sensitive unicode stuff, but doesn't touch
+    // uppercase ASCII characters.
+    const canonicalTldAtom = internals.canonicalizeAtom(tldAtom);
+
+    if (options.tldBlacklist) {
+        return !internals.includesMapped(
+            internals.normalizeTable(options.tldBlacklist),
+            internals.canonicalizeAtom, canonicalTldAtom);
+    }
+
+    return internals.includesMapped(
+        internals.normalizeTable(options.tldWhitelist),
+        internals.canonicalizeAtom, canonicalTldAtom);
+};
+
+
+/**
+ * Check whether the domain atoms has an address literal part followed by a
+ * normal domain atom part. For example, [127.0.0.1].com.
+ *
+ * @param {string[]} domainAtoms The parsed domain atoms.
+ * @returns {boolean} Whether there exists both a normal domain atom and an
+ *   address literal.
+ */
+internals.hasDomainLiteralThenAtom = function (domainAtoms) {
+
+    let hasDomainLiteral = false;
+    for (let i = 0; i < domainAtoms.length; ++i) {
+        if (domainAtoms[i][0] === '[') {
+            hasDomainLiteral = true;
+        }
+        else if (hasDomainLiteral) {
+            return true;
+        }
+    }
+
+    return false;
+};
+
+
+/**
+ * Check that an email address conforms to RFCs 5321, 5322, 6530 and others
+ *
+ * We distinguish clearly between a Mailbox as defined by RFC 5321 and an
+ * addr-spec as defined by RFC 5322. Depending on the context, either can be
+ * regarded as a valid email address. The RFC 5321 Mailbox specification is
+ * more restrictive (comments, white space and obsolete forms are not allowed).
+ *
+ * @param {string} email The email address to check. See README for specifics.
+ * @param {Object} options The (optional) options:
+ *   {*} errorLevel Determines the boundary between valid and invalid
+ *     addresses.
+ *   {*} tldBlacklist The set of domains to consider invalid.
+ *   {*} tldWhitelist The set of domains to consider valid.
+ *   {*} allowUnicode Whether to allow non-ASCII characters, defaults to true.
+ *   {*} minDomainAtoms The minimum number of domain atoms which must be present
+ *     for the address to be valid.
+ * @param {function(number|boolean)} callback The (optional) callback handler.
+ * @return {*}
+ */
+
+exports.validate = internals.validate = function (email, options, callback) {
+
+    options = options || {};
+
+    if (typeof email !== 'string') {
+        throw new TypeError('expected string email');
+    }
+
+    email = internals.normalize(email);
+
+    // The callback function is deprecated.
+    // $lab:coverage:off$
+    if (typeof options === 'function') {
+        callback = options;
+        options = {};
+    }
+
+    if (typeof callback !== 'function') {
+        callback = null;
+    }
+    // $lab:coverage:on$
+
+    let diagnose;
+    let threshold;
+
+    if (typeof options.errorLevel === 'number') {
+        diagnose = true;
+        threshold = options.errorLevel;
+    }
+    else {
+        diagnose = !!options.errorLevel;
+        threshold = internals.diagnoses.valid;
+    }
+
+    if (options.tldWhitelist) {
+        if (typeof options.tldWhitelist === 'string') {
+            options.tldWhitelist = [options.tldWhitelist];
+        }
+        else if (typeof options.tldWhitelist !== 'object') {
+            throw new TypeError('expected array or object tldWhitelist');
+        }
+    }
+
+    if (options.tldBlacklist) {
+        if (typeof options.tldBlacklist === 'string') {
+            options.tldBlacklist = [options.tldBlacklist];
+        }
+        else if (typeof options.tldBlacklist !== 'object') {
+            throw new TypeError('expected array or object tldBlacklist');
+        }
+    }
+
+    if (options.minDomainAtoms && (options.minDomainAtoms !== ((+options.minDomainAtoms) | 0) || options.minDomainAtoms < 0)) {
+        throw new TypeError('expected positive integer minDomainAtoms');
+    }
+
+    // Normalize the set of excluded diagnoses.
+    if (options.excludeDiagnoses) {
+        if (!internals.isIterable(options.excludeDiagnoses)) {
+            throw new TypeError('expected iterable excludeDiagnoses');
+        }
+
+        // This won't catch cross-realm Sets pre-Node 10, but it will cast the
+        // value to an in-realm Set representation.
+        if (!internals.isSet(options.excludeDiagnoses)) {
+            options.excludeDiagnoses = new Set(options.excludeDiagnoses);
+        }
+    }
+
+    let maxResult = internals.diagnoses.valid;
+    const updateResult = (value) => {
+
+        if (value > maxResult && (!options.excludeDiagnoses || !options.excludeDiagnoses.has(value))) {
+            maxResult = value;
+        }
+    };
+
+    const allowUnicode = options.allowUnicode === undefined || !!options.allowUnicode;
+    if (!allowUnicode && /[^\x00-\x7f]/.test(email)) {
+        updateResult(internals.diagnoses.undesiredNonAscii);
+    }
+
+    const context = {
+        now: internals.components.localpart,
+        prev: internals.components.localpart,
+        stack: [internals.components.localpart]
+    };
+
+    let prevToken = '';
+
+    const parseData = {
+        local: '',
+        domain: ''
+    };
+    const atomData = {
+        locals: [''],
+        domains: ['']
+    };
+
+    let elementCount = 0;
+    let elementLength = 0;
+    let crlfCount = 0;
+    let charCode;
+
+    let hyphenFlag = false;
+    let assertEnd = false;
+
+    const emailLength = email.length;
+
+    let token;                                      // Token is used outside the loop, must declare similarly
+    for (let i = 0; i < emailLength; i += token.length) {
+        // Utilize codepoints to account for Unicode surrogate pairs
+        token = String.fromCodePoint(email.codePointAt(i));
+
+        switch (context.now) {
+            // Local-part
+            case internals.components.localpart:
+                // http://tools.ietf.org/html/rfc5322#section-3.4.1
+                //   local-part      =   dot-atom / quoted-string / obs-local-part
+                //
+                //   dot-atom        =   [CFWS] dot-atom-text [CFWS]
+                //
+                //   dot-atom-text   =   1*atext *("." 1*atext)
+                //
+                //   quoted-string   =   [CFWS]
+                //                       DQUOTE *([FWS] qcontent) [FWS] DQUOTE
+                //                       [CFWS]
+                //
+                //   obs-local-part  =   word *("." word)
+                //
+                //   word            =   atom / quoted-string
+                //
+                //   atom            =   [CFWS] 1*atext [CFWS]
+                switch (token) {
+                    // Comment
+                    case '(':
+                        if (elementLength === 0) {
+                            // Comments are OK at the beginning of an element
+                            updateResult(elementCount === 0 ? internals.diagnoses.cfwsComment : internals.diagnoses.deprecatedComment);
+                        }
+                        else {
+                            updateResult(internals.diagnoses.cfwsComment);
+                            // Cannot start a comment in an element, should be end
+                            assertEnd = true;
+                        }
+
+                        context.stack.push(context.now);
+                        context.now = internals.components.contextComment;
+                        break;
+
+                        // Next dot-atom element
+                    case '.':
+                        if (elementLength === 0) {
+                            // Another dot, already?
+                            updateResult(elementCount === 0 ? internals.diagnoses.errDotStart : internals.diagnoses.errConsecutiveDots);
+                        }
+                        else {
+                            // The entire local-part can be a quoted string for RFC 5321; if one atom is quoted it's an RFC 5322 obsolete form
+                            if (assertEnd) {
+                                updateResult(internals.diagnoses.deprecatedLocalPart);
+                            }
+
+                            // CFWS & quoted strings are OK again now we're at the beginning of an element (although they are obsolete forms)
+                            assertEnd = false;
+                            elementLength = 0;
+                            ++elementCount;
+                            parseData.local += token;
+                            atomData.locals[elementCount] = '';
+                        }
+
+                        break;
+
+                        // Quoted string
+                    case '"':
+                        if (elementLength === 0) {
+                            // The entire local-part can be a quoted string for RFC 5321; if one atom is quoted it's an RFC 5322 obsolete form
+                            updateResult(elementCount === 0 ? internals.diagnoses.rfc5321QuotedString : internals.diagnoses.deprecatedLocalPart);
+
+                            parseData.local += token;
+                            atomData.locals[elementCount] += token;
+                            elementLength += Buffer.byteLength(token, 'utf8');
+
+                            // Quoted string must be the entire element
+                            assertEnd = true;
+                            context.stack.push(context.now);
+                            context.now = internals.components.contextQuotedString;
+                        }
+                        else {
+                            updateResult(internals.diagnoses.errExpectingATEXT);
+                        }
+
+                        break;
+
+                        // Folding white space
+                    case '\r':
+                        if (emailLength === ++i || email[i] !== '\n') {
+                            // Fatal error
+                            updateResult(internals.diagnoses.errCRNoLF);
+                            break;
+                        }
+
+                        // Fallthrough
+
+                    case ' ':
+                    case '\t':
+                        if (elementLength === 0) {
+                            updateResult(elementCount === 0 ? internals.diagnoses.cfwsFWS : internals.diagnoses.deprecatedFWS);
+                        }
+                        else {
+                            // We can't start FWS in the middle of an element, better be end
+                            assertEnd = true;
+                        }
+
+                        context.stack.push(context.now);
+                        context.now = internals.components.contextFWS;
+                        prevToken = token;
+                        break;
+
+                    case '@':
+                        // At this point we should have a valid local-part
+                        // $lab:coverage:off$
+                        if (context.stack.length !== 1) {
+                            throw new Error('unexpected item on context stack');
+                        }
+                        // $lab:coverage:on$
+
+                        if (parseData.local.length === 0) {
+                            // Fatal error
+                            updateResult(internals.diagnoses.errNoLocalPart);
+                        }
+                        else if (elementLength === 0) {
+                            // Fatal error
+                            updateResult(internals.diagnoses.errDotEnd);
+                        }
+                        // http://tools.ietf.org/html/rfc5321#section-4.5.3.1.1 the maximum total length of a user name or other local-part is 64
+                        //    octets
+                        else if (Buffer.byteLength(parseData.local, 'utf8') > 64) {
+                            updateResult(internals.diagnoses.rfc5322LocalTooLong);
+                        }
+                        // http://tools.ietf.org/html/rfc5322#section-3.4.1 comments and folding white space SHOULD NOT be used around "@" in the
+                        //    addr-spec
+                        //
+                        // http://tools.ietf.org/html/rfc2119
+                        // 4. SHOULD NOT this phrase, or the phrase "NOT RECOMMENDED" mean that there may exist valid reasons in particular
+                        //    circumstances when the particular behavior is acceptable or even useful, but the full implications should be understood
+                        //    and the case carefully weighed before implementing any behavior described with this label.
+                        else if (context.prev === internals.components.contextComment || context.prev === internals.components.contextFWS) {
+                            updateResult(internals.diagnoses.deprecatedCFWSNearAt);
+                        }
+
+                        // Clear everything down for the domain parsing
+                        context.now = internals.components.domain;
+                        context.stack[0] = internals.components.domain;
+                        elementCount = 0;
+                        elementLength = 0;
+                        assertEnd = false; // CFWS can only appear at the end of the element
+                        break;
+
+                        // ATEXT
+                    default:
+                        // http://tools.ietf.org/html/rfc5322#section-3.2.3
+                        //    atext = ALPHA / DIGIT / ; Printable US-ASCII
+                        //            "!" / "#" /     ;  characters not including
+                        //            "$" / "%" /     ;  specials.  Used for atoms.
+                        //            "&" / "'" /
+                        //            "*" / "+" /
+                        //            "-" / "/" /
+                        //            "=" / "?" /
+                        //            "^" / "_" /
+                        //            "`" / "{" /
+                        //            "|" / "}" /
+                        //            "~"
+                        if (assertEnd) {
+                            // We have encountered atext where it is no longer valid
+                            switch (context.prev) {
+                                case internals.components.contextComment:
+                                case internals.components.contextFWS:
+                                    updateResult(internals.diagnoses.errATEXTAfterCFWS);
+                                    break;
+
+                                case internals.components.contextQuotedString:
+                                    updateResult(internals.diagnoses.errATEXTAfterQS);
+                                    break;
+
+                                    // $lab:coverage:off$
+                                default:
+                                    throw new Error('more atext found where none is allowed, but unrecognized prev context: ' + context.prev);
+                                    // $lab:coverage:on$
+                            }
+                        }
+                        else {
+                            context.prev = context.now;
+                            charCode = token.codePointAt(0);
+
+                            // Especially if charCode == 10
+                            if (internals.specials(charCode) || internals.c0Controls(charCode) || internals.c1Controls(charCode)) {
+
+                                // Fatal error
+                                updateResult(internals.diagnoses.errExpectingATEXT);
+                            }
+
+                            parseData.local += token;
+                            atomData.locals[elementCount] += token;
+                            elementLength += Buffer.byteLength(token, 'utf8');
+                        }
+                }
+
+                break;
+
+            case internals.components.domain:
+                // http://tools.ietf.org/html/rfc5322#section-3.4.1
+                //   domain          =   dot-atom / domain-literal / obs-domain
+                //
+                //   dot-atom        =   [CFWS] dot-atom-text [CFWS]
+                //
+                //   dot-atom-text   =   1*atext *("." 1*atext)
+                //
+                //   domain-literal  =   [CFWS] "[" *([FWS] dtext) [FWS] "]" [CFWS]
+                //
+                //   dtext           =   %d33-90 /          ; Printable US-ASCII
+                //                       %d94-126 /         ;  characters not including
+                //                       obs-dtext          ;  "[", "]", or "\"
+                //
+                //   obs-domain      =   atom *("." atom)
+                //
+                //   atom            =   [CFWS] 1*atext [CFWS]
+
+                // http://tools.ietf.org/html/rfc5321#section-4.1.2
+                //   Mailbox        = Local-part "@" ( Domain / address-literal )
+                //
+                //   Domain         = sub-domain *("." sub-domain)
+                //
+                //   address-literal  = "[" ( IPv4-address-literal /
+                //                    IPv6-address-literal /
+                //                    General-address-literal ) "]"
+                //                    ; See Section 4.1.3
+
+                // http://tools.ietf.org/html/rfc5322#section-3.4.1
+                //      Note: A liberal syntax for the domain portion of addr-spec is
+                //      given here.  However, the domain portion contains addressing
+                //      information specified by and used in other protocols (e.g.,
+                //      [RFC1034], [RFC1035], [RFC1123], [RFC5321]).  It is therefore
+                //      incumbent upon implementations to conform to the syntax of
+                //      addresses for the context in which they are used.
+                //
+                // is_email() author's note: it's not clear how to interpret this in
+                // he context of a general email address validator. The conclusion I
+                // have reached is this: "addressing information" must comply with
+                // RFC 5321 (and in turn RFC 1035), anything that is "semantically
+                // invisible" must comply only with RFC 5322.
+                switch (token) {
+                    // Comment
+                    case '(':
+                        if (elementLength === 0) {
+                            // Comments at the start of the domain are deprecated in the text, comments at the start of a subdomain are obs-domain
+                            // http://tools.ietf.org/html/rfc5322#section-3.4.1
+                            updateResult(elementCount === 0 ? internals.diagnoses.deprecatedCFWSNearAt : internals.diagnoses.deprecatedComment);
+                        }
+                        else {
+                            // We can't start a comment mid-element, better be at the end
+                            assertEnd = true;
+                            updateResult(internals.diagnoses.cfwsComment);
+                        }
+
+                        context.stack.push(context.now);
+                        context.now = internals.components.contextComment;
+                        break;
+
+                        // Next dot-atom element
+                    case '.':
+                        const punycodeLength = Punycode.toASCII(atomData.domains[elementCount]).length;
+                        if (elementLength === 0) {
+                            // Another dot, already? Fatal error.
+                            updateResult(elementCount === 0 ? internals.diagnoses.errDotStart : internals.diagnoses.errConsecutiveDots);
+                        }
+                        else if (hyphenFlag) {
+                            // Previous subdomain ended in a hyphen. Fatal error.
+                            updateResult(internals.diagnoses.errDomainHyphenEnd);
+                        }
+                        else if (punycodeLength > 63) {
+                            // RFC 5890 specifies that domain labels that are encoded using the Punycode algorithm
+                            // must adhere to the <= 63 octet requirement.
+                            // This includes string prefixes from the Punycode algorithm.
+                            //
+                            // https://tools.ietf.org/html/rfc5890#section-2.3.2.1
+                            // labels          63 octets or less
+
+                            updateResult(internals.diagnoses.rfc5322LabelTooLong);
+                        }
+
+                        // CFWS is OK again now we're at the beginning of an element (although
+                        // it may be obsolete CFWS)
+                        assertEnd = false;
+                        elementLength = 0;
+                        ++elementCount;
+                        atomData.domains[elementCount] = '';
+                        parseData.domain += token;
+
+                        break;
+
+                        // Domain literal
+                    case '[':
+                        if (atomData.domains[elementCount].length === 0) {
+                            if (parseData.domain.length) {
+                                // Domain literal interspersed with domain refs.
+                                updateResult(internals.diagnoses.errDotAfterDomainLiteral);
+                            }
+
+                            assertEnd = true;
+                            elementLength += Buffer.byteLength(token, 'utf8');
+                            context.stack.push(context.now);
+                            context.now = internals.components.literal;
+                            parseData.domain += token;
+                            atomData.domains[elementCount] += token;
+                            parseData.literal = '';
+                        }
+                        else {
+                            // Fatal error
+                            updateResult(internals.diagnoses.errExpectingATEXT);
+                        }
+
+                        break;
+
+                        // Folding white space
+                    case '\r':
+                        if (emailLength === ++i || email[i] !== '\n') {
+                            // Fatal error
+                            updateResult(internals.diagnoses.errCRNoLF);
+                            break;
+                        }
+
+                        // Fallthrough
+
+                    case ' ':
+                    case '\t':
+                        if (elementLength === 0) {
+                            updateResult(elementCount === 0 ? internals.diagnoses.deprecatedCFWSNearAt : internals.diagnoses.deprecatedFWS);
+                        }
+                        else {
+                            // We can't start FWS in the middle of an element, so this better be the end
+                            updateResult(internals.diagnoses.cfwsFWS);
+                            assertEnd = true;
+                        }
+
+                        context.stack.push(context.now);
+                        context.now = internals.components.contextFWS;
+                        prevToken = token;
+                        break;
+
+                        // This must be ATEXT
+                    default:
+                        // RFC 5322 allows any atext...
+                        // http://tools.ietf.org/html/rfc5322#section-3.2.3
+                        //    atext = ALPHA / DIGIT / ; Printable US-ASCII
+                        //            "!" / "#" /     ;  characters not including
+                        //            "$" / "%" /     ;  specials.  Used for atoms.
+                        //            "&" / "'" /
+                        //            "*" / "+" /
+                        //            "-" / "/" /
+                        //            "=" / "?" /
+                        //            "^" / "_" /
+                        //            "`" / "{" /
+                        //            "|" / "}" /
+                        //            "~"
+
+                        // But RFC 5321 only allows letter-digit-hyphen to comply with DNS rules
+                        //   (RFCs 1034 & 1123)
+                        // http://tools.ietf.org/html/rfc5321#section-4.1.2
+                        //   sub-domain     = Let-dig [Ldh-str]
+                        //
+                        //   Let-dig        = ALPHA / DIGIT
+                        //
+                        //   Ldh-str        = *( ALPHA / DIGIT / "-" ) Let-dig
+                        //
+                        if (assertEnd) {
+                            // We have encountered ATEXT where it is no longer valid
+                            switch (context.prev) {
+                                case internals.components.contextComment:
+                                case internals.components.contextFWS:
+                                    updateResult(internals.diagnoses.errATEXTAfterCFWS);
+                                    break;
+
+                                case internals.components.literal:
+                                    updateResult(internals.diagnoses.errATEXTAfterDomainLiteral);
+                                    break;
+
+                                    // $lab:coverage:off$
+                                default:
+                                    throw new Error('more atext found where none is allowed, but unrecognized prev context: ' + context.prev);
+                                    // $lab:coverage:on$
+                            }
+                        }
+
+                        charCode = token.codePointAt(0);
+                        // Assume this token isn't a hyphen unless we discover it is
+                        hyphenFlag = false;
+
+                        if (internals.specials(charCode) || internals.c0Controls(charCode) || internals.c1Controls(charCode)) {
+                            // Fatal error
+                            updateResult(internals.diagnoses.errExpectingATEXT);
+                        }
+                        else if (token === '-') {
+                            if (elementLength === 0) {
+                                // Hyphens cannot be at the beginning of a subdomain, fatal error
+                                updateResult(internals.diagnoses.errDomainHyphenStart);
+                            }
+
+                            hyphenFlag = true;
+                        }
+                        // Check if it's a neither a number nor a latin/unicode letter
+                        else if (charCode < 48 || (charCode > 122 && charCode < 192) || (charCode > 57 && charCode < 65) || (charCode > 90 && charCode < 97)) {
+                            // This is not an RFC 5321 subdomain, but still OK by RFC 5322
+                            updateResult(internals.diagnoses.rfc5322Domain);
+                        }
+
+                        parseData.domain += token;
+                        atomData.domains[elementCount] += token;
+                        elementLength += Buffer.byteLength(token, 'utf8');
+                }
+
+                break;
+
+                // Domain literal
+            case internals.components.literal:
+                // http://tools.ietf.org/html/rfc5322#section-3.4.1
+                //   domain-literal  =   [CFWS] "[" *([FWS] dtext) [FWS] "]" [CFWS]
+                //
+                //   dtext           =   %d33-90 /          ; Printable US-ASCII
+                //                       %d94-126 /         ;  characters not including
+                //                       obs-dtext          ;  "[", "]", or "\"
+                //
+                //   obs-dtext       =   obs-NO-WS-CTL / quoted-pair
+                switch (token) {
+                    // End of domain literal
+                    case ']':
+                        if (maxResult < internals.categories.deprecated) {
+                            // Could be a valid RFC 5321 address literal, so let's check
+
+                            // http://tools.ietf.org/html/rfc5321#section-4.1.2
+                            //   address-literal  = "[" ( IPv4-address-literal /
+                            //                    IPv6-address-literal /
+                            //                    General-address-literal ) "]"
+                            //                    ; See Section 4.1.3
+                            //
+                            // http://tools.ietf.org/html/rfc5321#section-4.1.3
+                            //   IPv4-address-literal  = Snum 3("."  Snum)
+                            //
+                            //   IPv6-address-literal  = "IPv6:" IPv6-addr
+                            //
+                            //   General-address-literal  = Standardized-tag ":" 1*dcontent
+                            //
+                            //   Standardized-tag  = Ldh-str
+                            //                     ; Standardized-tag MUST be specified in a
+                            //                     ; Standards-Track RFC and registered with IANA
+                            //
+                            //   dcontent      = %d33-90 / ; Printable US-ASCII
+                            //                 %d94-126 ; excl. "[", "\", "]"
+                            //
+                            //   Snum          = 1*3DIGIT
+                            //                 ; representing a decimal integer
+                            //                 ; value in the range 0 through 255
+                            //
+                            //   IPv6-addr     = IPv6-full / IPv6-comp / IPv6v4-full / IPv6v4-comp
+                            //
+                            //   IPv6-hex      = 1*4HEXDIG
+                            //
+                            //   IPv6-full     = IPv6-hex 7(":" IPv6-hex)
+                            //
+                            //   IPv6-comp     = [IPv6-hex *5(":" IPv6-hex)] "::"
+                            //                 [IPv6-hex *5(":" IPv6-hex)]
+                            //                 ; The "::" represents at least 2 16-bit groups of
+                            //                 ; zeros.  No more than 6 groups in addition to the
+                            //                 ; "::" may be present.
+                            //
+                            //   IPv6v4-full   = IPv6-hex 5(":" IPv6-hex) ":" IPv4-address-literal
+                            //
+                            //   IPv6v4-comp   = [IPv6-hex *3(":" IPv6-hex)] "::"
+                            //                 [IPv6-hex *3(":" IPv6-hex) ":"]
+                            //                 IPv4-address-literal
+                            //                 ; The "::" represents at least 2 16-bit groups of
+                            //                 ; zeros.  No more than 4 groups in addition to the
+                            //                 ; "::" and IPv4-address-literal may be present.
+
+                            let index = -1;
+                            let addressLiteral = parseData.literal;
+                            const matchesIP = internals.regex.ipV4.exec(addressLiteral);
+
+                            // Maybe extract IPv4 part from the end of the address-literal
+                            if (matchesIP) {
+                                index = matchesIP.index;
+                                if (index !== 0) {
+                                    // Convert IPv4 part to IPv6 format for futher testing
+                                    addressLiteral = addressLiteral.slice(0, index) + '0:0';
+                                }
+                            }
+
+                            if (index === 0) {
+                                // Nothing there except a valid IPv4 address, so...
+                                updateResult(internals.diagnoses.rfc5321AddressLiteral);
+                            }
+                            else if (addressLiteral.slice(0, 5).toLowerCase() !== 'ipv6:') {
+                                updateResult(internals.diagnoses.rfc5322DomainLiteral);
+                            }
+                            else {
+                                const match = addressLiteral.slice(5);
+                                let maxGroups = internals.maxIPv6Groups;
+                                const groups = match.split(':');
+                                index = match.indexOf('::');
+
+                                if (!~index) {
+                                    // Need exactly the right number of groups
+                                    if (groups.length !== maxGroups) {
+                                        updateResult(internals.diagnoses.rfc5322IPv6GroupCount);
+                                    }
+                                }
+                                else if (index !== match.lastIndexOf('::')) {
+                                    updateResult(internals.diagnoses.rfc5322IPv62x2xColon);
+                                }
+                                else {
+                                    if (index === 0 || index === match.length - 2) {
+                                        // RFC 4291 allows :: at the start or end of an address with 7 other groups in addition
+                                        ++maxGroups;
+                                    }
+
+                                    if (groups.length > maxGroups) {
+                                        updateResult(internals.diagnoses.rfc5322IPv6MaxGroups);
+                                    }
+                                    else if (groups.length === maxGroups) {
+                                        // Eliding a single "::"
+                                        updateResult(internals.diagnoses.deprecatedIPv6);
+                                    }
+                                }
+
+                                // IPv6 testing strategy
+                                if (match[0] === ':' && match[1] !== ':') {
+                                    updateResult(internals.diagnoses.rfc5322IPv6ColonStart);
+                                }
+                                else if (match[match.length - 1] === ':' && match[match.length - 2] !== ':') {
+                                    updateResult(internals.diagnoses.rfc5322IPv6ColonEnd);
+                                }
+                                else if (internals.checkIpV6(groups)) {
+                                    updateResult(internals.diagnoses.rfc5321AddressLiteral);
+                                }
+                                else {
+                                    updateResult(internals.diagnoses.rfc5322IPv6BadCharacter);
+                                }
+                            }
+                        }
+                        else {
+                            updateResult(internals.diagnoses.rfc5322DomainLiteral);
+                        }
+
+                        parseData.domain += token;
+                        atomData.domains[elementCount] += token;
+                        elementLength += Buffer.byteLength(token, 'utf8');
+                        context.prev = context.now;
+                        context.now = context.stack.pop();
+                        break;
+
+                    case '\\':
+                        updateResult(internals.diagnoses.rfc5322DomainLiteralOBSDText);
+                        context.stack.push(context.now);
+                        context.now = internals.components.contextQuotedPair;
+                        break;
+
+                        // Folding white space
+                    case '\r':
+                        if (emailLength === ++i || email[i] !== '\n') {
+                            updateResult(internals.diagnoses.errCRNoLF);
+                            break;
+                        }
+
+                        // Fallthrough
+
+                    case ' ':
+                    case '\t':
+                        updateResult(internals.diagnoses.cfwsFWS);
+
+                        context.stack.push(context.now);
+                        context.now = internals.components.contextFWS;
+                        prevToken = token;
+                        break;
+
+                        // DTEXT
+                    default:
+                        // http://tools.ietf.org/html/rfc5322#section-3.4.1
+                        //   dtext         =   %d33-90 /  ; Printable US-ASCII
+                        //                     %d94-126 / ;  characters not including
+                        //                     obs-dtext  ;  "[", "]", or "\"
+                        //
+                        //   obs-dtext     =   obs-NO-WS-CTL / quoted-pair
+                        //
+                        //   obs-NO-WS-CTL =   %d1-8 /    ; US-ASCII control
+                        //                     %d11 /     ;  characters that do not
+                        //                     %d12 /     ;  include the carriage
+                        //                     %d14-31 /  ;  return, line feed, and
+                        //                     %d127      ;  white space characters
+                        charCode = token.codePointAt(0);
+
+                        // '\r', '\n', ' ', and '\t' have already been parsed above
+                        if ((charCode !== 127 && internals.c1Controls(charCode)) || charCode === 0 || token === '[') {
+                            // Fatal error
+                            updateResult(internals.diagnoses.errExpectingDTEXT);
+                            break;
+                        }
+                        else if (internals.c0Controls(charCode) || charCode === 127) {
+                            updateResult(internals.diagnoses.rfc5322DomainLiteralOBSDText);
+                        }
+
+                        parseData.literal += token;
+                        parseData.domain += token;
+                        atomData.domains[elementCount] += token;
+                        elementLength += Buffer.byteLength(token, 'utf8');
+                }
+
+                break;
+
+                // Quoted string
+            case internals.components.contextQuotedString:
+                // http://tools.ietf.org/html/rfc5322#section-3.2.4
+                //   quoted-string = [CFWS]
+                //                   DQUOTE *([FWS] qcontent) [FWS] DQUOTE
+                //                   [CFWS]
+                //
+                //   qcontent      = qtext / quoted-pair
+                switch (token) {
+                    // Quoted pair
+                    case '\\':
+                        context.stack.push(context.now);
+                        context.now = internals.components.contextQuotedPair;
+                        break;
+
+                        // Folding white space. Spaces are allowed as regular characters inside a quoted string - it's only FWS if we include '\t' or '\r\n'
+                    case '\r':
+                        if (emailLength === ++i || email[i] !== '\n') {
+                            // Fatal error
+                            updateResult(internals.diagnoses.errCRNoLF);
+                            break;
+                        }
+
+                        // Fallthrough
+
+                    case '\t':
+                        // http://tools.ietf.org/html/rfc5322#section-3.2.2
+                        //   Runs of FWS, comment, or CFWS that occur between lexical tokens in
+                        //   a structured header field are semantically interpreted as a single
+                        //   space character.
+
+                        // http://tools.ietf.org/html/rfc5322#section-3.2.4
+                        //   the CRLF in any FWS/CFWS that appears within the quoted-string [is]
+                        //   semantically "invisible" and therefore not part of the
+                        //   quoted-string
+
+                        parseData.local += ' ';
+                        atomData.locals[elementCount] += ' ';
+                        elementLength += Buffer.byteLength(token, 'utf8');
+
+                        updateResult(internals.diagnoses.cfwsFWS);
+                        context.stack.push(context.now);
+                        context.now = internals.components.contextFWS;
+                        prevToken = token;
+                        break;
+
+                        // End of quoted string
+                    case '"':
+                        parseData.local += token;
+                        atomData.locals[elementCount] += token;
+                        elementLength += Buffer.byteLength(token, 'utf8');
+                        context.prev = context.now;
+                        context.now = context.stack.pop();
+                        break;
+
+                        // QTEXT
+                    default:
+                        // http://tools.ietf.org/html/rfc5322#section-3.2.4
+                        //   qtext          =   %d33 /             ; Printable US-ASCII
+                        //                      %d35-91 /          ;  characters not including
+                        //                      %d93-126 /         ;  "\" or the quote character
+                        //                      obs-qtext
+                        //
+                        //   obs-qtext      =   obs-NO-WS-CTL
+                        //
+                        //   obs-NO-WS-CTL  =   %d1-8 /            ; US-ASCII control
+                        //                      %d11 /             ;  characters that do not
+                        //                      %d12 /             ;  include the carriage
+                        //                      %d14-31 /          ;  return, line feed, and
+                        //                      %d127              ;  white space characters
+                        charCode = token.codePointAt(0);
+
+                        if ((charCode !== 127 && internals.c1Controls(charCode)) || charCode === 0 || charCode === 10) {
+                            updateResult(internals.diagnoses.errExpectingQTEXT);
+                        }
+                        else if (internals.c0Controls(charCode) || charCode === 127) {
+                            updateResult(internals.diagnoses.deprecatedQTEXT);
+                        }
+
+                        parseData.local += token;
+                        atomData.locals[elementCount] += token;
+                        elementLength += Buffer.byteLength(token, 'utf8');
+                }
+
+                // http://tools.ietf.org/html/rfc5322#section-3.4.1
+                //   If the string can be represented as a dot-atom (that is, it contains
+                //   no characters other than atext characters or "." surrounded by atext
+                //   characters), then the dot-atom form SHOULD be used and the quoted-
+                //   string form SHOULD NOT be used.
+
+                break;
+                // Quoted pair
+            case internals.components.contextQuotedPair:
+                // http://tools.ietf.org/html/rfc5322#section-3.2.1
+                //   quoted-pair     =   ("\" (VCHAR / WSP)) / obs-qp
+                //
+                //   VCHAR           =  %d33-126   ; visible (printing) characters
+                //   WSP             =  SP / HTAB  ; white space
+                //
+                //   obs-qp          =   "\" (%d0 / obs-NO-WS-CTL / LF / CR)
+                //
+                //   obs-NO-WS-CTL   =   %d1-8 /   ; US-ASCII control
+                //                       %d11 /    ;  characters that do not
+                //                       %d12 /    ;  include the carriage
+                //                       %d14-31 / ;  return, line feed, and
+                //                       %d127     ;  white space characters
+                //
+                // i.e. obs-qp       =  "\" (%d0-8, %d10-31 / %d127)
+                charCode = token.codePointAt(0);
+
+                if (charCode !== 127 &&  internals.c1Controls(charCode)) {
+                    // Fatal error
+                    updateResult(internals.diagnoses.errExpectingQPair);
+                }
+                else if ((charCode < 31 && charCode !== 9) || charCode === 127) {
+                    // ' ' and '\t' are allowed
+                    updateResult(internals.diagnoses.deprecatedQP);
+                }
+
+                // At this point we know where this qpair occurred so we could check to see if the character actually needed to be quoted at all.
+                // http://tools.ietf.org/html/rfc5321#section-4.1.2
+                //   the sending system SHOULD transmit the form that uses the minimum quoting possible.
+
+                context.prev = context.now;
+                // End of qpair
+                context.now = context.stack.pop();
+                const escapeToken = '\\' + token;
+
+                switch (context.now) {
+                    case internals.components.contextComment:
+                        break;
+
+                    case internals.components.contextQuotedString:
+                        parseData.local += escapeToken;
+                        atomData.locals[elementCount] += escapeToken;
+
+                        // The maximum sizes specified by RFC 5321 are octet counts, so we must include the backslash
+                        elementLength += 2;
+                        break;
+
+                    case internals.components.literal:
+                        parseData.domain += escapeToken;
+                        atomData.domains[elementCount] += escapeToken;
+
+                        // The maximum sizes specified by RFC 5321 are octet counts, so we must include the backslash
+                        elementLength += 2;
+                        break;
+
+                        // $lab:coverage:off$
+                    default:
+                        throw new Error('quoted pair logic invoked in an invalid context: ' + context.now);
+                        // $lab:coverage:on$
+                }
+
+                break;
+
+                // Comment
+            case internals.components.contextComment:
+                // http://tools.ietf.org/html/rfc5322#section-3.2.2
+                //   comment  = "(" *([FWS] ccontent) [FWS] ")"
+                //
+                //   ccontent = ctext / quoted-pair / comment
+                switch (token) {
+                    // Nested comment
+                    case '(':
+                        // Nested comments are ok
+                        context.stack.push(context.now);
+                        context.now = internals.components.contextComment;
+                        break;
+
+                        // End of comment
+                    case ')':
+                        context.prev = context.now;
+                        context.now = context.stack.pop();
+                        break;
+
+                        // Quoted pair
+                    case '\\':
+                        context.stack.push(context.now);
+                        context.now = internals.components.contextQuotedPair;
+                        break;
+
+                        // Folding white space
+                    case '\r':
+                        if (emailLength === ++i || email[i] !== '\n') {
+                            // Fatal error
+                            updateResult(internals.diagnoses.errCRNoLF);
+                            break;
+                        }
+
+                        // Fallthrough
+
+                    case ' ':
+                    case '\t':
+                        updateResult(internals.diagnoses.cfwsFWS);
+
+                        context.stack.push(context.now);
+                        context.now = internals.components.contextFWS;
+                        prevToken = token;
+                        break;
+
+                        // CTEXT
+                    default:
+                        // http://tools.ietf.org/html/rfc5322#section-3.2.3
+                        //   ctext         = %d33-39 /  ; Printable US-ASCII
+                        //                   %d42-91 /  ;  characters not including
+                        //                   %d93-126 / ;  "(", ")", or "\"
+                        //                   obs-ctext
+                        //
+                        //   obs-ctext     = obs-NO-WS-CTL
+                        //
+                        //   obs-NO-WS-CTL = %d1-8 /    ; US-ASCII control
+                        //                   %d11 /     ;  characters that do not
+                        //                   %d12 /     ;  include the carriage
+                        //                   %d14-31 /  ;  return, line feed, and
+                        //                   %d127      ;  white space characters
+                        charCode = token.codePointAt(0);
+
+                        if (charCode === 0 || charCode === 10 || (charCode !== 127 && internals.c1Controls(charCode))) {
+                            // Fatal error
+                            updateResult(internals.diagnoses.errExpectingCTEXT);
+                            break;
+                        }
+                        else if (internals.c0Controls(charCode) || charCode === 127) {
+                            updateResult(internals.diagnoses.deprecatedCTEXT);
+                        }
+                }
+
+                break;
+
+                // Folding white space
+            case internals.components.contextFWS:
+                // http://tools.ietf.org/html/rfc5322#section-3.2.2
+                //   FWS     =   ([*WSP CRLF] 1*WSP) /  obs-FWS
+                //                                   ; Folding white space
+
+                // But note the erratum:
+                // http://www.rfc-editor.org/errata_search.php?rfc=5322&eid=1908:
+                //   In the obsolete syntax, any amount of folding white space MAY be
+                //   inserted where the obs-FWS rule is allowed.  This creates the
+                //   possibility of having two consecutive "folds" in a line, and
+                //   therefore the possibility that a line which makes up a folded header
+                //   field could be composed entirely of white space.
+                //
+                //   obs-FWS =   1*([CRLF] WSP)
+
+                if (prevToken === '\r') {
+                    if (token === '\r') {
+                        // Fatal error
+                        updateResult(internals.diagnoses.errFWSCRLFx2);
+                        break;
+                    }
+
+                    if (++crlfCount > 1) {
+                        // Multiple folds => obsolete FWS
+                        updateResult(internals.diagnoses.deprecatedFWS);
+                    }
+                    else {
+                        crlfCount = 1;
+                    }
+                }
+
+                switch (token) {
+                    case '\r':
+                        if (emailLength === ++i || email[i] !== '\n') {
+                            // Fatal error
+                            updateResult(internals.diagnoses.errCRNoLF);
+                        }
+
+                        break;
+
+                    case ' ':
+                    case '\t':
+                        break;
+
+                    default:
+                        if (prevToken === '\r') {
+                            // Fatal error
+                            updateResult(internals.diagnoses.errFWSCRLFEnd);
+                        }
+
+                        crlfCount = 0;
+
+                        // End of FWS
+                        context.prev = context.now;
+                        context.now = context.stack.pop();
+
+                        // Look at this token again in the parent context
+                        --i;
+                }
+
+                prevToken = token;
+                break;
+
+                // Unexpected context
+                // $lab:coverage:off$
+            default:
+                throw new Error('unknown context: ' + context.now);
+                // $lab:coverage:on$
+        } // Primary state machine
+
+        if (maxResult > internals.categories.rfc5322) {
+            // Fatal error, no point continuing
+            break;
+        }
+    } // Token loop
+
+    // Check for errors
+    if (maxResult < internals.categories.rfc5322) {
+        const punycodeLength = Punycode.toASCII(parseData.domain).length;
+        // Fatal errors
+        if (context.now === internals.components.contextQuotedString) {
+            updateResult(internals.diagnoses.errUnclosedQuotedString);
+        }
+        else if (context.now === internals.components.contextQuotedPair) {
+            updateResult(internals.diagnoses.errBackslashEnd);
+        }
+        else if (context.now === internals.components.contextComment) {
+            updateResult(internals.diagnoses.errUnclosedComment);
+        }
+        else if (context.now === internals.components.literal) {
+            updateResult(internals.diagnoses.errUnclosedDomainLiteral);
+        }
+        else if (token === '\r') {
+            updateResult(internals.diagnoses.errFWSCRLFEnd);
+        }
+        else if (parseData.domain.length === 0) {
+            updateResult(internals.diagnoses.errNoDomain);
+        }
+        else if (elementLength === 0) {
+            updateResult(internals.diagnoses.errDotEnd);
+        }
+        else if (hyphenFlag) {
+            updateResult(internals.diagnoses.errDomainHyphenEnd);
+        }
+
+        // Other errors
+        else if (punycodeLength > 255) {
+            // http://tools.ietf.org/html/rfc5321#section-4.5.3.1.2
+            //   The maximum total length of a domain name or number is 255 octets.
+            updateResult(internals.diagnoses.rfc5322DomainTooLong);
+        }
+        else if (Buffer.byteLength(parseData.local, 'utf8') + punycodeLength + /* '@' */ 1 > 254) {
+            // http://tools.ietf.org/html/rfc5321#section-4.1.2
+            //   Forward-path   = Path
+            //
+            //   Path           = "<" [ A-d-l ":" ] Mailbox ">"
+            //
+            // http://tools.ietf.org/html/rfc5321#section-4.5.3.1.3
+            //   The maximum total length of a reverse-path or forward-path is 256 octets (including the punctuation and element separators).
+            //
+            // Thus, even without (obsolete) routing information, the Mailbox can only be 254 characters long. This is confirmed by this verified
+            // erratum to RFC 3696:
+            //
+            // http://www.rfc-editor.org/errata_search.php?rfc=3696&eid=1690
+            //   However, there is a restriction in RFC 2821 on the length of an address in MAIL and RCPT commands of 254 characters.  Since
+            //   addresses that do not fit in those fields are not normally useful, the upper limit on address lengths should normally be considered
+            //   to be 254.
+            updateResult(internals.diagnoses.rfc5322TooLong);
+        }
+        else if (elementLength > 63) {
+            // http://tools.ietf.org/html/rfc1035#section-2.3.4
+            // labels   63 octets or less
+            updateResult(internals.diagnoses.rfc5322LabelTooLong);
+        }
+        else if (options.minDomainAtoms && atomData.domains.length < options.minDomainAtoms && (atomData.domains.length !== 1 || atomData.domains[0][0] !== '[')) {
+            updateResult(internals.diagnoses.errDomainTooShort);
+        }
+        else if (internals.hasDomainLiteralThenAtom(atomData.domains)) {
+            updateResult(internals.diagnoses.errDotAfterDomainLiteral);
+        }
+        else if (options.tldWhitelist || options.tldBlacklist) {
+            const tldAtom = atomData.domains[elementCount];
+
+            if (!internals.validDomain(tldAtom, options)) {
+                updateResult(internals.diagnoses.errUnknownTLD);
+            }
+        }
+    } // Check for errors
+
+    // Finish
+    if (maxResult < internals.categories.dnsWarn) {
+        // Per RFC 5321, domain atoms are limited to letter-digit-hyphen, so we only need to check code <= 57 to check for a digit
+        const code = atomData.domains[elementCount].codePointAt(0);
+
+        if (code <= 57) {
+            updateResult(internals.diagnoses.rfc5321TLDNumeric);
+        }
+    }
+
+    if (maxResult < threshold) {
+        maxResult = internals.diagnoses.valid;
+    }
+
+    const finishResult = diagnose ? maxResult : maxResult < internals.defaultThreshold;
+
+    // $lab:coverage:off$
+    if (callback) {
+        callback(finishResult);
+    }
+    // $lab:coverage:on$
+
+    return finishResult;
+};
+
+
+exports.diagnoses = internals.validate.diagnoses = (function () {
+
+    const diag = {};
+    const keys = Object.keys(internals.diagnoses);
+    for (let i = 0; i < keys.length; ++i) {
+        const key = keys[i];
+        diag[key] = internals.diagnoses[key];
+    }
+
+    return diag;
+})();
+
+
+exports.normalize = internals.normalize;