1 files changed, 93 insertions, 0 deletions
diff --git a/node_modules/markdown-it-anchor/index.js b/node_modules/markdown-it-anchor/index.js
new file mode 100644
index 00000000..1a087b58
--- /dev/null
+++ b/node_modules/markdown-it-anchor/index.js
@@ -0,0 +1,93 @@
+const slugify = (s) => encodeURIComponent(String(s).trim().toLowerCase().replace(/\s+/g, '-'))
+
+const position = {
+  false: 'push',
+  true: 'unshift'
+}
+
+const hasProp = Object.prototype.hasOwnProperty
+
+const permalinkHref = slug => `#${slug}`
+
+const renderPermalink = (slug, opts, state, idx) => {
+  const space = () => Object.assign(new state.Token('text', '', 0), { content: ' ' })
+
+  const linkTokens = [
+    Object.assign(new state.Token('link_open', 'a', 1), {
+      attrs: [
+        ['class', opts.permalinkClass],
+        ['href', opts.permalinkHref(slug, state)],
+        ['aria-hidden', 'true']
+      ]
+    }),
+    Object.assign(new state.Token('html_block', '', 0), { content: opts.permalinkSymbol }),
+    new state.Token('link_close', 'a', -1)
+  ]
+
+  // `push` or `unshift` according to position option.
+  // Space is at the opposite side.
+  linkTokens[position[!opts.permalinkBefore]](space())
+  state.tokens[idx + 1].children[position[opts.permalinkBefore]](...linkTokens)
+}
+
+const uniqueSlug = (slug, slugs) => {
+  let uniq = slug
+  let i = 2
+  while (hasProp.call(slugs, uniq)) uniq = `${slug}-${i++}`
+  slugs[uniq] = true
+  return uniq
+}
+
+const isLevelSelectedNumber = selection => level => level >= selection
+const isLevelSelectedArray = selection => level => selection.includes(level)
+
+const anchor = (md, opts) => {
+  opts = Object.assign({}, anchor.defaults, opts)
+
+  md.core.ruler.push('anchor', state => {
+    const slugs = {}
+    const tokens = state.tokens
+
+    const isLevelSelected = Array.isArray(opts.level)
+      ? isLevelSelectedArray(opts.level)
+      : isLevelSelectedNumber(opts.level)
+
+    tokens
+      .filter(token => token.type === 'heading_open')
+      .filter(token => isLevelSelected(Number(token.tag.substr(1))))
+      .forEach(token => {
+        // Aggregate the next token children text.
+        const title = tokens[tokens.indexOf(token) + 1].children
+          .filter(token => token.type === 'text' || token.type === 'code_inline')
+          .reduce((acc, t) => acc + t.content, '')
+
+        let slug = token.attrGet('id')
+
+        if (slug == null) {
+          slug = uniqueSlug(opts.slugify(title), slugs)
+          token.attrPush(['id', slug])
+        }
+
+        if (opts.permalink) {
+          opts.renderPermalink(slug, opts, state, tokens.indexOf(token))
+        }
+
+        if (opts.callback) {
+          opts.callback(token, { slug, title })
+        }
+      })
+  })
+}
+
+anchor.defaults = {
+  level: 1,
+  slugify,
+  permalink: false,
+  renderPermalink,
+  permalinkClass: 'header-anchor',
+  permalinkSymbol: '¶',
+  permalinkBefore: false,
+  permalinkHref
+}
+
+module.exports = anchor