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