capitalize.js (1627B)
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 format = require( './../../format' ); 25 26 27 // MAIN // 28 29 /** 30 * Capitalizes the first character in a string. 31 * 32 * @param {string} str - input string 33 * @throws {TypeError} must provide a string primitive 34 * @returns {string} capitalized string 35 * 36 * @example 37 * var out = capitalize( 'last man standing' ); 38 * // returns 'Last man standing' 39 * 40 * @example 41 * var out = capitalize( 'presidential election' ); 42 * // returns 'Presidential election' 43 * 44 * @example 45 * var out = capitalize( 'javaScript' ); 46 * // returns 'JavaScript' 47 * 48 * @example 49 * var out = capitalize( 'Hidden Treasures' ); 50 * // returns 'Hidden Treasures' 51 */ 52 function capitalize( str ) { 53 if ( !isString( str ) ) { 54 throw new TypeError( format( 'invalid argument. First argument must be a string. Value: `%s`.', str ) ); 55 } 56 if ( str === '' ) { 57 return ''; 58 } 59 return str.charAt( 0 ).toUpperCase() + str.slice( 1 ); 60 } 61 62 63 // EXPORTS // 64 65 module.exports = capitalize;