/**
* @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 isString = require( '@stdlib/assert-is-string' ).isPrimitive;
var reRegExp = require( '@stdlib/regexp-regexp' );
var format = require( '@stdlib/string-format' );


// MAIN //

/**
* Parses a regular expression string and returns a new regular expression.
*
* @param {string} str - regular expression string
* @throws {TypeError} must provide a regular expression string
* @returns {(RegExp|null)} regular expression or null
*
* @example
* var re = reFromString( '/beep/' );
* // returns /beep/
*/
function reFromString( str ) {
	if ( !isString( str ) ) {
		throw new TypeError( format( 'invalid argument. Must provide a regular expression string. Value: `%s`.', str ) );
	}
	// Capture the regular expression pattern and any flags:
	str = reRegExp().exec( str );

	// Create a new regular expression:
	return ( str ) ? new RegExp( str[1], str[2] ) : null;
}


// EXPORTS //

module.exports = reFromString;