/** * @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 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 [ 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 ] */ 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( 'invalid argument. Must provide either an Array, Typed Array, or an array-like Object. Value: `'+collection+'`.' ); } // EXPORTS // module.exports = shift;