startcase.js (1625B)
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( '@stdlib/assert/is-string' ).isPrimitive; 24 var reWhitespace = require( '@stdlib/regexp/whitespace' ); 25 var format = require( './../../format' ); 26 27 28 // MAIN // 29 30 /** 31 * Capitalizes the first letter of each word in an input string. 32 * 33 * @param {string} str - string to convert 34 * @throws {TypeError} must provide a string 35 * @returns {string} start case string 36 * 37 * @example 38 * var str = startcase( 'beep boop foo bar' ); 39 * // returns 'Beep Boop Foo Bar' 40 */ 41 function startcase( str ) { 42 var cap; 43 var out; 44 var ch; 45 var i; 46 if ( !isString( str ) ) { 47 throw new TypeError( format( 'invalid argument. Must provide a string. Value: `%s`.', str ) ); 48 } 49 cap = true; 50 out = ''; 51 for ( i = 0; i < str.length; i++ ) { 52 ch = str.charAt( i ); 53 if ( reWhitespace.REGEXP.test( ch ) ) { 54 out += ch; 55 cap = true; 56 } else if ( cap ) { 57 out += ch.toUpperCase(); 58 cap = false; 59 } else { 60 out += ch; 61 } 62 } 63 return out; 64 } 65 66 67 // EXPORTS // 68 69 module.exports = startcase;