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77 lines
1.9 KiB
77 lines
1.9 KiB
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var Promise = require('any-promise') |
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var assert = require('assert') |
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module.exports = thenify |
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/** |
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* Turn async functions into promises |
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* |
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* @param {Function} fn |
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* @return {Function} |
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* @api public |
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*/ |
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function thenify(fn, options) { |
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assert(typeof fn === 'function') |
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return createWrapper(fn, options) |
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} |
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/** |
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* Turn async functions into promises and backward compatible with callback |
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* |
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* @param {Function} fn |
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* @return {Function} |
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* @api public |
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*/ |
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thenify.withCallback = function (fn, options) { |
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assert(typeof fn === 'function') |
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options = options || {} |
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options.withCallback = true |
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return createWrapper(fn, options) |
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} |
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function createCallback(resolve, reject, multiArgs) { |
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// default to true |
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if (multiArgs === undefined) multiArgs = true |
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return function(err, value) { |
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if (err) return reject(err) |
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var length = arguments.length |
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if (length <= 2 || !multiArgs) return resolve(value) |
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if (Array.isArray(multiArgs)) { |
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var values = {} |
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for (var i = 1; i < length; i++) values[multiArgs[i - 1]] = arguments[i] |
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return resolve(values) |
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} |
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var values = new Array(length - 1) |
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for (var i = 1; i < length; ++i) values[i - 1] = arguments[i] |
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resolve(values) |
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} |
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} |
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function createWrapper(fn, options) { |
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options = options || {} |
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var name = fn.name; |
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name = (name || '').replace(/\s|bound(?!$)/g, '') |
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var newFn = function () { |
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var self = this |
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var len = arguments.length |
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if (options.withCallback) { |
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var lastType = typeof arguments[len - 1] |
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if (lastType === 'function') return fn.apply(self, arguments) |
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} |
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var args = new Array(len + 1) |
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for (var i = 0; i < len; ++i) args[i] = arguments[i] |
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var lastIndex = i |
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return new Promise(function (resolve, reject) { |
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args[lastIndex] = createCallback(resolve, reject, options.multiArgs) |
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fn.apply(self, args) |
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}) |
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} |
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Object.defineProperty(newFn, 'name', { value: name }) |
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return newFn |
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}
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