48 lines
1.1 KiB
JavaScript
48 lines
1.1 KiB
JavaScript
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module.exports = {
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promisify,
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promisifyObject
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};
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/**
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* Promisifies a function wich follows the (err, res) => {} pattern as last
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* function argument and returns the promisified version.
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*
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* @param {Function} fn Function to promisify
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* @return {Function} The promisified function
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*/
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function promisify(fn) {
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return function(...args) {
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let thisArg = this;
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let orgCb = args[args.length - 1];
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if (typeof orgCb !== 'function') orgCb = null;
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return new Promise(function(resolve, reject) {
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function cb(err, res) {
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if (orgCb) orgCb(err, res);
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err ? reject(err) : resolve(res);
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}
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if (orgCb)
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args[args.length - 1] = cb;
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else
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args.push(cb);
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fn.apply(thisArg, args);
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});
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};
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}
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/**
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* Promisifies object methods.
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*
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* @param {Object} obj Object to promisify
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* @param {Array<String>} methods Array of method names to promisify
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*/
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function promisifyObject(obj, methods) {
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for (let method of methods) {
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let orgMethod = obj[method];
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obj[method] = promisify(orgMethod);
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}
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}
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