@stdlib/utils/shift/lib/shift_typed_array.js

Standard utilities.

/**
* @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 //

/**
* Removes and returns the first element of a typed array.
*
* @private
* @param {TypedArray} arr - input array
* @returns {Array} input array and the removed element
*
* @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( arr ) {
	var offset;
	var view;
	var v;
	if ( arr.length === 0 ) {
		return [ arr, void 0 ];
	}
	v = arr[ 0 ];
	offset = arr.byteOffset + arr.BYTES_PER_ELEMENT;
	view = new arr.constructor( arr.buffer, offset, arr.length-1 );
	return [ view, v ];
}


// EXPORTS //

module.exports = shift;