from_string.js (1503B)
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 reRegExp = require( '@stdlib/regexp/regexp' ); 25 26 27 // MAIN // 28 29 /** 30 * Parses a regular expression string and returns a new regular expression. 31 * 32 * @param {string} str - regular expression string 33 * @throws {TypeError} must provide a regular expression string 34 * @returns {(RegExp|null)} regular expression or null 35 * 36 * @example 37 * var re = reFromString( '/beep/' ); 38 * // returns /beep/ 39 */ 40 function reFromString( str ) { 41 if ( !isString( str ) ) { 42 throw new TypeError( 'invalid argument. Must provide a regular expression string. Value: `' + str + '`.' ); 43 } 44 // Capture the regular expression pattern and any flags: 45 str = reRegExp().exec( str ); 46 47 // Create a new regular expression: 48 return ( str ) ? new RegExp( str[1], str[2] ) : null; 49 } 50 51 52 // EXPORTS // 53 54 module.exports = reFromString;