81 lines
2.3 KiB
JavaScript
81 lines
2.3 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 shiftObject = require( './shift_object.js' );
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var shiftTypedArray = require( './shift_typed_array.js' );
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// MAIN //
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/**
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* Removes and returns the first element of a collection.
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*
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* @param {(Array|TypedArray|Object)} collection - collection
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* @throws {TypeError} must provide either an array, typed array, or an array-like object
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* @returns {Array} updated collection and the removed element
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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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* var out = shift( arr );
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* // returns [ [ 2.0, 3.0, 4.0, 5.0 ], 1.0 ]
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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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* var out = shift( arr );
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* // returns [ <Float64Array>[ 2.0, 3.0, 4.0, 5.0 ], 1.0 ]
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*/
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function shift( collection ) {
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var v;
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if ( isArray( collection ) ) {
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v = collection.shift();
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return [ collection, v ];
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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 shiftTypedArray( collection );
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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 shiftObject( collection );
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}
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throw new TypeError( 'invalid argument. Must provide 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 = shift;
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