61 lines
1.5 KiB
JavaScript
61 lines
1.5 KiB
JavaScript
'use strict';
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var isPromise = require('is-promise');
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/**
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* Return a function that will run a function asynchronously or synchronously
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*
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* example:
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* runAsync(wrappedFunction, callback)(...args);
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*
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* @param {Function} func Function to run
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* @param {Function} cb Callback function passed the `func` returned value
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* @return {Function(arguments)} Arguments to pass to `func`. This function will in turn
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* return a Promise (Node >= 0.12) or call the callbacks.
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*/
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var runAsync = module.exports = function (func, cb) {
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cb = cb || function () {};
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return function () {
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var async = false;
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var args = arguments;
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var promise = new Promise(function (resolve, reject) {
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var answer = func.apply({
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async: function () {
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async = true;
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return function (err, value) {
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if (err) {
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reject(err);
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} else {
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resolve(value);
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}
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};
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}
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}, Array.prototype.slice.call(args));
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if (!async) {
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if (isPromise(answer)) {
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answer.then(resolve, reject);
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} else {
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resolve(answer);
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}
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}
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});
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promise.then(cb.bind(null, null), cb);
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return promise;
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}
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};
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runAsync.cb = function (func, cb) {
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return runAsync(function () {
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var args = Array.prototype.slice.call(arguments);
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if (args.length === func.length - 1) {
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args.push(this.async());
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}
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return func.apply(this, args);
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}, cb);
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};
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