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47 lines
1.2 KiB
47 lines
1.2 KiB
'use strict';
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/// encapsulate a method with a node-style callback in a Promise
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/// @param {object} 'this' of the encapsulated function
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/// @param {function} function to be encapsulated
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/// @param {Array-like} args to be passed to the called function
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/// @return {Promise} a Promise encapuslaing the function
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module.exports.promise = function (fn, context, args) {
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//can't do anything without Promise so fail silently
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if (typeof Promise === 'undefined') {
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return;
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}
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if (!Array.isArray(args)) {
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args = Array.prototype.slice.call(args);
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}
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if (typeof fn !== 'function') {
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return Promise.reject(new Error('fn must be a function'));
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}
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return new Promise(function(resolve, reject) {
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args.push(function(err, data) {
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if (err) {
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reject(err);
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} else {
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resolve(data);
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}
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});
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fn.apply(context, args);
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});
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};
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/// @param {err} the error to be thrown
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module.exports.reject = function (err) {
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// silently swallow errors if Promise is not defined
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// emulating old behavior
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if (typeof Promise === 'undefined') {
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return;
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}
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return Promise.reject(err);
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};
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