main.js (1480B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2018 The Stdlib Authors. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 'use strict'; 20 21 // MODULES // 22 23 var isString = require( './../../is-string' ); 24 25 26 // MAIN // 27 28 /** 29 * Tests if a value is an alphagram. 30 * 31 * @param {*} x - value to test 32 * @returns {boolean} boolean indicating if a value is an alphagram 33 * 34 * @example 35 * var out = isAlphagram( 'beep' ); 36 * // returns true 37 * 38 * @example 39 * var out = isAlphagram( new String( 'beep' ) ); 40 * // returns true 41 * 42 * @example 43 * var out = isAlphagram( 'zba' ); 44 * // returns false 45 * 46 * @example 47 * var out = isAlphagram( '' ); 48 * // returns false 49 * 50 * @example 51 * var out = isAlphagram( 123 ); 52 * // returns false 53 */ 54 function isAlphagram( x ) { 55 var len; 56 var i; 57 58 if ( !isString( x ) ) { 59 return false; 60 } 61 len = x.length; 62 if ( !len ) { 63 return false; 64 } 65 for ( i = 1; i < len; i++ ) { 66 if ( x[ i-1 ] > x[ i ] ) { 67 return false; 68 } 69 } 70 return true; 71 } 72 73 74 // EXPORTS // 75 76 module.exports = isAlphagram;