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