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'use strict';
var extend = require('extend-shallow');
var safe = require('safe-regex');
/**
* The main export is a function that takes a `pattern` string and an `options` object.
*
* ```js
& var not = require('regex-not');
& console.log(not('foo'));
& //=> /^(?:(?!^(?:foo)$).)*$/
* ```
*
* @param {String} `pattern`
* @param {Object} `options`
* @return {RegExp} Converts the given `pattern` to a regex using the specified `options`.
* @api public
*/
function toRegex(pattern, options) {
return new RegExp(toRegex.create(pattern, options));
}
/**
* Create a regex-compatible string from the given `pattern` and `options`.
*
* ```js
& var not = require('regex-not');
& console.log(not.create('foo'));
& //=> '^(?:(?!^(?:foo)$).)*$'
* ```
* @param {String} `pattern`
* @param {Object} `options`
* @return {String}
* @api public
*/
toRegex.create = function(pattern, options) {
if (typeof pattern !== 'string') {
throw new TypeError('expected a string');
}
var opts = extend({}, options);
if (opts.contains === true) {
opts.strictNegate = false;
}
var open = opts.strictOpen !== false ? '^' : '';
var close = opts.strictClose !== false ? '$' : '';
var endChar = opts.endChar ? opts.endChar : '+';
var str = pattern;
if (opts.strictNegate === false) {
str = '(?:(?!(?:' + pattern + ')).)' + endChar;
} else {
str = '(?:(?!^(?:' + pattern + ')$).)' + endChar;
}
var res = open + str + close;
if (opts.safe === true && safe(res) === false) {
throw new Error('potentially unsafe regular expression: ' + res);
}
return res;
};
/**
* Expose `toRegex`
*/
module.exports = toRegex;