65 lines
1.4 KiB
JavaScript
65 lines
1.4 KiB
JavaScript
|
/**
|
||
|
|
* @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';
|
||
|
|
|
||
|
|
// MAIN //
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Adds elements from a collection to the beginning of an array-like object.
|
||
|
|
*
|
||
|
|
* @private
|
||
|
|
* @param {Object} obj - input array-like object
|
||
|
|
* @param {ArrayLike} items - items to add
|
||
|
|
* @returns {Object} input object
|
||
|
|
*
|
||
|
|
* @example
|
||
|
|
* var obj = {
|
||
|
|
* 'length': 2,
|
||
|
|
* '0': 1.0,
|
||
|
|
* '1': 2.0
|
||
|
|
* };
|
||
|
|
*
|
||
|
|
* obj = prepend( obj, [ 3.0, 4.0 ] );
|
||
|
|
* // returns { 'length': 4, '0': 3.0, '1': 4.0, '2': 1.0, '3': 2.0 }
|
||
|
|
*/
|
||
|
|
function prepend( obj, items ) {
|
||
|
|
var len;
|
||
|
|
var n;
|
||
|
|
var i;
|
||
|
|
|
||
|
|
len = obj.length;
|
||
|
|
n = items.length;
|
||
|
|
|
||
|
|
// Shift all existing elements to the right...
|
||
|
|
for ( i = len-1; i >= 0; i-- ) {
|
||
|
|
obj[ i+n ] = obj[ i ];
|
||
|
|
}
|
||
|
|
// Add new elements...
|
||
|
|
for ( i = 0; i < n; i++ ) {
|
||
|
|
obj[ i ] = items[ i ];
|
||
|
|
}
|
||
|
|
obj.length = len + n;
|
||
|
|
return obj;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
// EXPORTS //
|
||
|
|
|
||
|
|
module.exports = prepend;
|