82 lines
2.0 KiB
JavaScript
82 lines
2.0 KiB
JavaScript
|
/**
|
||
|
|
* @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;
|
||
|
|
|
||
|
|
|
||
|
|
// VARIABLES //
|
||
|
|
|
||
|
|
var RE_CHARS = /[-\/\\^$*+?.()|[\]{}]/g; // eslint-disable-line no-useless-escape
|
||
|
|
|
||
|
|
|
||
|
|
// MAIN //
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Escapes a regular expression string.
|
||
|
|
*
|
||
|
|
* @param {string} str - regular expression string
|
||
|
|
* @throws {TypeError} first argument must be a string primitive
|
||
|
|
* @returns {string} escaped string
|
||
|
|
*
|
||
|
|
* @example
|
||
|
|
* var str = rescape( '[A-Z]*' );
|
||
|
|
* // returns '\\[A\\-Z\\]\\*'
|
||
|
|
*/
|
||
|
|
function rescape( str ) {
|
||
|
|
var len;
|
||
|
|
var s;
|
||
|
|
var i;
|
||
|
|
|
||
|
|
if ( !isString( str ) ) {
|
||
|
|
throw new TypeError( 'invalid argument. Must provide a regular expression string. Value: `' + str + '`.' );
|
||
|
|
}
|
||
|
|
// Check if the string starts with a forward slash...
|
||
|
|
if ( str[ 0 ] === '/' ) {
|
||
|
|
// Find the last forward slash...
|
||
|
|
len = str.length;
|
||
|
|
for ( i = len-1; i >= 0; i-- ) {
|
||
|
|
if ( str[ i ] === '/' ) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
// If we searched the string to no avail or if the first letter is not `/`, assume that the string is not of the form `/[...]/[guimy]`:
|
||
|
|
if ( i === void 0 || i <= 0 ) {
|
||
|
|
return str.replace( RE_CHARS, '\\$&' );
|
||
|
|
}
|
||
|
|
// We need to de-construct the string...
|
||
|
|
s = str.substring( 1, i );
|
||
|
|
|
||
|
|
// Only escape the characters between the `/`:
|
||
|
|
s = s.replace( RE_CHARS, '\\$&' );
|
||
|
|
|
||
|
|
// Reassemble:
|
||
|
|
str = str[ 0 ] + s + str.substring( i );
|
||
|
|
|
||
|
|
return str;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
// EXPORTS //
|
||
|
|
|
||
|
|
module.exports = rescape;
|