27 lines
753 B
JavaScript
27 lines
753 B
JavaScript
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'use strict';
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/*eslint-disable prefer-arrow-callback*/
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/**
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* Function to convert a callback function into a promise
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*
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* @see http://eddmann.com/posts/promisifying-error-first-asynchronous-callbacks-in-javascript/
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* @example promisify(fs.readFile)('hello.txt', 'utf8')
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* .then(console.log)
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* .catch(console.error)
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* @param {Function} fn - the callback function to convert
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* @return {Promise} - the new promise
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*/
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function promisify(fn) {
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return function () {
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let args = [].slice.call(arguments);
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return new Promise(function (resolve, reject) {
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fn.apply(undefined, args.concat((error, value) => {
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return error ? reject(error) : resolve(value);
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}));
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});
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};
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}
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module.exports = promisify;
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/*eslint-enable prefer-arrow-callback*/
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