@stdlib/utils-copy/lib/main.js

Copy or deep clone a value to an arbitrary depth.

/**
* @license Apache-2.0
*
* Copyright (c) 2018 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*    http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

'use strict';

// MODULES //

var isArray = require( '@stdlib/assert-is-array' );
var isNonNegativeInteger = require( '@stdlib/assert-is-nonnegative-integer' ).isPrimitive;
var format = require( '@stdlib/string-format' );
var PINF = require( '@stdlib/constants-float64-pinf' );
var deepCopy = require( './deep_copy.js' );


// MAIN //

/**
* Copies or deep clones a value to an arbitrary depth.
*
* @param {*} value - value to copy
* @param {NonNegativeInteger} [level=+infinity] - copy depth
* @throws {TypeError} second argument must be a nonnegative integer
* @returns {*} value copy
*
* @example
* var out = copy( 'beep' );
* // returns 'beep'
*
* @example
* var value = [
*     {
*         'a': 1,
*         'b': true,
*         'c': [ 1, 2, 3 ]
*     }
* ];
* var out = copy( value );
* // returns [ { 'a': 1, 'b': true, 'c': [ 1, 2, 3 ] } ]
*
* var bool = ( value[0].c === out[0].c );
* // returns false
*/
function copy( value, level ) {
	var out;
	if ( arguments.length > 1 ) {
		if ( !isNonNegativeInteger( level ) ) {
			throw new TypeError( format( 'invalid argument. Second argument must be a nonnegative integer. Value: `%s`.', level ) );
		}
		if ( level === 0 ) {
			return value;
		}
	} else {
		level = PINF;
	}
	out = ( isArray( value ) ) ? new Array( value.length ) : {};
	return deepCopy( value, out, [value], [out], level );
}


// EXPORTS //

module.exports = copy;