index.js•1.22 kB
/*!
* merge-descriptors
* Copyright(c) 2014 Jonathan Ong
* Copyright(c) 2015 Douglas Christopher Wilson
* MIT Licensed
*/
'use strict'
/**
* Module exports.
* @public
*/
module.exports = merge
/**
* Module variables.
* @private
*/
var hasOwnProperty = Object.prototype.hasOwnProperty
/**
* Merge the property descriptors of `src` into `dest`
*
* @param {object} dest Object to add descriptors to
* @param {object} src Object to clone descriptors from
* @param {boolean} [redefine=true] Redefine `dest` properties with `src` properties
* @returns {object} Reference to dest
* @public
*/
function merge (dest, src, redefine) {
if (!dest) {
throw new TypeError('argument dest is required')
}
if (!src) {
throw new TypeError('argument src is required')
}
if (redefine === undefined) {
// Default to true
redefine = true
}
Object.getOwnPropertyNames(src).forEach(function forEachOwnPropertyName (name) {
if (!redefine && hasOwnProperty.call(dest, name)) {
// Skip descriptor
return
}
// Copy descriptor
var descriptor = Object.getOwnPropertyDescriptor(src, name)
Object.defineProperty(dest, name, descriptor)
})
return dest
}