74 lines
1.8 KiB
JavaScript
74 lines
1.8 KiB
JavaScript
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'use strict'
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module.exports = function (PromiseArgument) {
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var Promise;
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function throat(size, fn) {
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var queue = []
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function run(fn, self, args) {
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if (size) {
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size--
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var result = new Promise(function (resolve) {
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resolve(fn.apply(self, args))
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})
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result.then(release, release)
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return result
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} else {
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return new Promise(function (resolve) {
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queue.push(new Delayed(resolve, fn, self, args))
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})
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}
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}
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function release() {
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size++
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if (queue.length) {
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var next = queue.shift()
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next.resolve(run(next.fn, next.self, next.args))
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}
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}
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if (typeof size === 'function' && typeof fn === 'number') {
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var temp = fn;
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fn = size;
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size = temp;
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}
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if (typeof fn === 'function') {
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return function () {
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var args = [];
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for (var i = 0; i < arguments.length; i++) {
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args.push(arguments[i]);
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}
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return run(fn, this, args)
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}
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} else {
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return function (fn) {
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var args = [];
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for (var i = 1; i < arguments.length; i++) {
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args.push(arguments[i]);
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}
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return run(fn, this, args)
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}
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}
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}
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if (typeof arguments[0] === 'number' || typeof arguments[1] === 'number') {
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Promise = module.exports.Promise;
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if (typeof Promise !== 'function') {
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throw new Error('You must provide a Promise polyfill for this library to work in older environments');
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}
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return throat(arguments[0], arguments[1]);
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} else {
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Promise = PromiseArgument;
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return throat;
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}
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}
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/* istanbul ignore next */
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if (typeof Promise === 'function') {
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module.exports.Promise = Promise;
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}
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function Delayed(resolve, fn, self, args) {
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this.resolve = resolve
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this.fn = fn
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this.self = self || null
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this.args = args
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}
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