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Diffstat (limited to 'node_modules/when/lib/decorators/flow.js')
| -rw-r--r-- | node_modules/when/lib/decorators/flow.js | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/node_modules/when/lib/decorators/flow.js b/node_modules/when/lib/decorators/flow.js new file mode 100644 index 00000000..635e4f49 --- /dev/null +++ b/node_modules/when/lib/decorators/flow.js @@ -0,0 +1,160 @@ +/** @license MIT License (c) copyright 2010-2014 original author or authors */ +/** @author Brian Cavalier */ +/** @author John Hann */ + +(function(define) { 'use strict'; +define(function() { + + return function flow(Promise) { + + var resolve = Promise.resolve; + var reject = Promise.reject; + var origCatch = Promise.prototype['catch']; + + /** + * Handle the ultimate fulfillment value or rejection reason, and assume + * responsibility for all errors. If an error propagates out of result + * or handleFatalError, it will be rethrown to the host, resulting in a + * loud stack track on most platforms and a crash on some. + * @param {function?} onResult + * @param {function?} onError + * @returns {undefined} + */ + Promise.prototype.done = function(onResult, onError) { + this._handler.visit(this._handler.receiver, onResult, onError); + }; + + /** + * Add Error-type and predicate matching to catch. Examples: + * promise.catch(TypeError, handleTypeError) + * .catch(predicate, handleMatchedErrors) + * .catch(handleRemainingErrors) + * @param onRejected + * @returns {*} + */ + Promise.prototype['catch'] = Promise.prototype.otherwise = function(onRejected) { + if (arguments.length < 2) { + return origCatch.call(this, onRejected); + } + + if(typeof onRejected !== 'function') { + return this.ensure(rejectInvalidPredicate); + } + + return origCatch.call(this, createCatchFilter(arguments[1], onRejected)); + }; + + /** + * Wraps the provided catch handler, so that it will only be called + * if the predicate evaluates truthy + * @param {?function} handler + * @param {function} predicate + * @returns {function} conditional catch handler + */ + function createCatchFilter(handler, predicate) { + return function(e) { + return evaluatePredicate(e, predicate) + ? handler.call(this, e) + : reject(e); + }; + } + + /** + * Ensures that onFulfilledOrRejected will be called regardless of whether + * this promise is fulfilled or rejected. onFulfilledOrRejected WILL NOT + * receive the promises' value or reason. Any returned value will be disregarded. + * onFulfilledOrRejected may throw or return a rejected promise to signal + * an additional error. + * @param {function} handler handler to be called regardless of + * fulfillment or rejection + * @returns {Promise} + */ + Promise.prototype['finally'] = Promise.prototype.ensure = function(handler) { + if(typeof handler !== 'function') { + return this; + } + + return this.then(function(x) { + return runSideEffect(handler, this, identity, x); + }, function(e) { + return runSideEffect(handler, this, reject, e); + }); + }; + + function runSideEffect (handler, thisArg, propagate, value) { + var result = handler.call(thisArg); + return maybeThenable(result) + ? propagateValue(result, propagate, value) + : propagate(value); + } + + function propagateValue (result, propagate, x) { + return resolve(result).then(function () { + return propagate(x); + }); + } + + /** + * Recover from a failure by returning a defaultValue. If defaultValue + * is a promise, it's fulfillment value will be used. If defaultValue is + * a promise that rejects, the returned promise will reject with the + * same reason. + * @param {*} defaultValue + * @returns {Promise} new promise + */ + Promise.prototype['else'] = Promise.prototype.orElse = function(defaultValue) { + return this.then(void 0, function() { + return defaultValue; + }); + }; + + /** + * Shortcut for .then(function() { return value; }) + * @param {*} value + * @return {Promise} a promise that: + * - is fulfilled if value is not a promise, or + * - if value is a promise, will fulfill with its value, or reject + * with its reason. + */ + Promise.prototype['yield'] = function(value) { + return this.then(function() { + return value; + }); + }; + + /** + * Runs a side effect when this promise fulfills, without changing the + * fulfillment value. + * @param {function} onFulfilledSideEffect + * @returns {Promise} + */ + Promise.prototype.tap = function(onFulfilledSideEffect) { + return this.then(onFulfilledSideEffect)['yield'](this); + }; + + return Promise; + }; + + function rejectInvalidPredicate() { + throw new TypeError('catch predicate must be a function'); + } + + function evaluatePredicate(e, predicate) { + return isError(predicate) ? e instanceof predicate : predicate(e); + } + + function isError(predicate) { + return predicate === Error + || (predicate != null && predicate.prototype instanceof Error); + } + + function maybeThenable(x) { + return (typeof x === 'object' || typeof x === 'function') && x !== null; + } + + function identity(x) { + return x; + } + +}); +}(typeof define === 'function' && define.amd ? define : function(factory) { module.exports = factory(); })); |
