87 lines
2.6 KiB
JavaScript
87 lines
2.6 KiB
JavaScript
/**
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* @license Apache-2.0
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*
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* Copyright (c) 2018 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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// MODULES //
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var isArray = require( '@stdlib/assert/is-array' );
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var isTypedArrayLike = require( '@stdlib/assert/is-typed-array-like' );
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var isInteger = require( '@stdlib/assert/is-integer' );
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var unshiftArray = require( './unshift_array.js' );
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var unshiftObject = require( './unshift_object.js' );
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var unshiftTypedArray = require( './unshift_typed_array.js' );
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// MAIN //
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/**
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* Adds one or more elements to the beginning of a collection.
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*
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* @param {(Array|TypedArray|Object)} collection - collection
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* @param {...*} items - items to add
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* @throws {TypeError} must provide either an array, typed array, or an array-like object
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* @returns {(Array|TypedArray|Object)} updated collection
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*
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* @example
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* var arr = [ 1.0, 2.0, 3.0, 4.0, 5.0 ];
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*
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* arr = unshift( arr, 6.0, 7.0 );
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* // returns [ 6.0, 7.0, 1.0, 2.0, 3.0, 4.0, 5.0 ]
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*
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* @example
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* var Float64Array = require( '@stdlib/array/float64' );
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*
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* var arr = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
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* // returns <Float64Array>[ 1.0, 2.0, 3.0, 4.0, 5.0 ]
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*
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* arr = unshift( arr, 6.0, 7.0 );
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* // returns <Float64Array>[ 6.0, 7.0, 1.0, 2.0, 3.0, 4.0, 5.0 ]
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*/
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function unshift( collection ) {
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var items;
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var i;
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items = new Array( arguments.length-1 );
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for ( i = 0; i < arguments.length-1; i++ ) {
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items[ i ] = arguments[ i+1 ];
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}
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if ( isArray( collection ) ) {
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return unshiftArray( collection, items );
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}
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// Check for a typed-array-like object, as verifying actual typed arrays is expensive...
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if ( isTypedArrayLike( collection ) ) {
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return unshiftTypedArray( collection, items );
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}
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// Check for an array-like object...
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if (
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collection !== null &&
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typeof collection === 'object' &&
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typeof collection.length === 'number' &&
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isInteger( collection.length ) &&
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collection.length >= 0
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) {
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return unshiftObject( collection, items );
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}
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throw new TypeError( 'invalid argument. First argument must be either an Array, Typed Array, or an array-like Object. Value: `'+collection+'`.' );
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}
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// EXPORTS //
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module.exports = unshift;
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