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* @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 isTypedArrayLike = require( '@stdlib/assert/is-typed-array-like' );
var isInteger = require( '@stdlib/assert/is-integer' );
var format = require( '@stdlib/string/format' );
var shiftObject = require( './shift_object.js' );
var shiftTypedArray = require( './shift_typed_array.js' );
// MAIN //
/**
* Removes and returns the first element of a collection.
*
* @param {(Array|TypedArray|Object)} collection - collection
* @throws {TypeError} must provide either an array, typed array, or an array-like object
* @returns {Array} updated collection and the removed element
*
* @example
* var arr = [ 1.0, 2.0, 3.0, 4.0, 5.0 ];
*
* var out = shift( arr );
* // returns [ [ 2.0, 3.0, 4.0, 5.0 ], 1.0 ]
*
* @example
* var Float64Array = require( '@stdlib/array/float64' );
*
* var arr = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
* // returns <Float64Array>[ 1.0, 2.0, 3.0, 4.0, 5.0 ]
*
* var out = shift( arr );
* // returns [ <Float64Array>[ 2.0, 3.0, 4.0, 5.0 ], 1.0 ]
*/
function shift( collection ) {
var v;
if ( isArray( collection ) ) {
v = collection.shift();
return [ collection, v ];
}
// Check for a typed-array-like object, as verifying actual typed arrays is expensive...
if ( isTypedArrayLike( collection ) ) {
return shiftTypedArray( collection );
}
// Check for an array-like object...
if (
collection !== null &&
typeof collection === 'object' &&
typeof collection.length === 'number' &&
isInteger( collection.length ) &&
collection.length >= 0
) {
return shiftObject( collection );
}
throw new TypeError( format( 'invalid argument. Must provide either an array, typed array, or an array-like object. Value: `%s`.', collection ) );
}
// EXPORTS //
module.exports = shift;
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