cyclic-copy.js

cyclic-copy.js

var utils = {
	forEach: function (obj, fn, ctx) {
		if (obj === null || typeof obj === 'undefined') {
			return
		}

		if (obj instanceof Array) {
			for (var i = 0; i < obj.length; i++) {
				if (fn.call(ctx, obj[i], i, obj)) {
					break
				}
			}
			return
		}
		var keys = Object.keys(obj), key
		while ((key = keys.shift())) {
			if (fn.call(ctx, obj[key], key, obj)) {
				break
			}
		}
	},

	copy: function copy(obj, map) {
		if (typeof obj !== 'object') { return obj }

		map = map || new WeakMap()

		var copied,
			Constructor = obj.constructor;

		switch (Constructor) {
			case RegExp: copied = new Constructor(obj); break;
			case Date: copied = new Constructor(obj.getTime()); break;
			default: copied = new Constructor();
		}

		map.set(obj, copied)

		utils.forEach(obj, function (value, key) {
			copied[key] = map.get(value) || copy(value, map)
		})

		return copied
	}
}

module.exports = utils