345 lines
12 KiB
Markdown
345 lines
12 KiB
Markdown
# Regenerate [](https://travis-ci.org/mathiasbynens/regenerate) [](https://codecov.io/gh/mathiasbynens/regenerate) [](https://gemnasium.com/mathiasbynens/regenerate)
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_Regenerate_ is a Unicode-aware regex generator for JavaScript. It allows you to easily generate ES5-compatible regular expressions based on a given set of Unicode symbols or code points. (This is trickier than you might think, because of [how JavaScript deals with astral symbols](https://mathiasbynens.be/notes/javascript-unicode).)
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## Installation
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Via [npm](https://npmjs.org/):
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```bash
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npm install regenerate
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```
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Via [Bower](http://bower.io/):
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```bash
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bower install regenerate
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```
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Via [Component](https://github.com/component/component):
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```bash
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component install mathiasbynens/regenerate
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```
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In a browser:
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```html
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<script src="regenerate.js"></script>
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```
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In [Node.js](https://nodejs.org/), [io.js](https://iojs.org/), and [RingoJS ≥ v0.8.0](http://ringojs.org/):
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```js
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var regenerate = require('regenerate');
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```
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In [Narwhal](http://narwhaljs.org/) and [RingoJS ≤ v0.7.0](http://ringojs.org/):
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```js
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var regenerate = require('regenerate').regenerate;
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```
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In [Rhino](http://www.mozilla.org/rhino/):
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```js
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load('regenerate.js');
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```
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Using an AMD loader like [RequireJS](http://requirejs.org/):
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```js
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require(
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{
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'paths': {
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'regenerate': 'path/to/regenerate'
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}
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},
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['regenerate'],
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function(regenerate) {
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console.log(regenerate);
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}
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);
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```
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## API
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### `regenerate(value1, value2, value3, ...)`
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The main Regenerate function. Calling this function creates a new set that gets a chainable API.
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```js
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var set = regenerate()
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.addRange(0x60, 0x69) // add U+0060 to U+0069
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.remove(0x62, 0x64) // remove U+0062 and U+0064
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.add(0x1D306); // add U+1D306
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set.valueOf();
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// → [0x60, 0x61, 0x63, 0x65, 0x66, 0x67, 0x68, 0x69, 0x1D306]
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set.toString();
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// → '[`ace-i]|\\uD834\\uDF06'
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set.toRegExp();
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// → /[`ace-i]|\uD834\uDF06/
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```
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Any arguments passed to `regenerate()` will be added to the set right away. Both code points (numbers) and symbols (strings consisting of a single Unicode symbol) are accepted, as well as arrays containing values of these types.
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```js
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regenerate(0x1D306, 'A', '©', 0x2603).toString();
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// → '[A\\xA9\\u2603]|\\uD834\\uDF06'
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var items = [0x1D306, 'A', '©', 0x2603];
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regenerate(items).toString();
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// → '[A\\xA9\\u2603]|\\uD834\\uDF06'
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```
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### `regenerate.prototype.add(value1, value2, value3, ...)`
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Any arguments passed to `add()` are added to the set. Both code points (numbers) and symbols (strings consisting of a single Unicode symbol) are accepted, as well as arrays containing values of these types.
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```js
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regenerate().add(0x1D306, 'A', '©', 0x2603).toString();
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// → '[A\\xA9\\u2603]|\\uD834\\uDF06'
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var items = [0x1D306, 'A', '©', 0x2603];
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regenerate().add(items).toString();
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// → '[A\\xA9\\u2603]|\\uD834\\uDF06'
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```
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It’s also possible to pass in a Regenerate instance. Doing so adds all code points in that instance to the current set.
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```js
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var set = regenerate(0x1D306, 'A');
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regenerate().add('©', 0x2603).add(set).toString();
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// → '[A\\xA9\\u2603]|\\uD834\\uDF06'
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```
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Note that the initial call to `regenerate()` acts like `add()`. This allows you to create a new Regenerate instance and add some code points to it in one go:
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```js
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regenerate(0x1D306, 'A', '©', 0x2603).toString();
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// → '[A\\xA9\\u2603]|\\uD834\\uDF06'
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```
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### `regenerate.prototype.remove(value1, value2, value3, ...)`
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Any arguments passed to `remove()` are removed to the set. Both code points (numbers) and symbols (strings consisting of a single Unicode symbol) are accepted, as well as arrays containing values of these types.
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```js
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regenerate(0x1D306, 'A', '©', 0x2603).remove('☃').toString();
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// → '[A\\xA9]|\\uD834\\uDF06'
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```
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It’s also possible to pass in a Regenerate instance. Doing so removes all code points in that instance from the current set.
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```js
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var set = regenerate('☃');
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regenerate(0x1D306, 'A', '©', 0x2603).remove(set).toString();
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// → '[A\\xA9]|\\uD834\\uDF06'
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```
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### `regenerate.prototype.addRange(start, end)`
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Adds a range of code points from `start` to `end` (inclusive) to the set. Both code points (numbers) and symbols (strings consisting of a single Unicode symbol) are accepted.
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```js
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regenerate(0x1D306).addRange(0x00, 0xFF).toString(16);
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// → '[\\0-\\xFF]|\\uD834\\uDF06'
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regenerate().addRange('A', 'z').toString();
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// → '[A-z]'
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```
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### `regenerate.prototype.removeRange(start, end)`
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Removes a range of code points from `start` to `end` (inclusive) from the set. Both code points (numbers) and symbols (strings consisting of a single Unicode symbol) are accepted.
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```js
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regenerate()
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.addRange(0x000000, 0x10FFFF) // add all Unicode code points
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.removeRange('A', 'z') // remove all symbols from `A` to `z`
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.toString();
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// → '[\\0-@\\{-\\uD7FF\\uE000-\\uFFFF]|[\\uD800-\\uDBFF][\\uDC00-\\uDFFF]|[\\uD800-\\uDBFF](?![\\uDC00-\\uDFFF])|(?:[^\\uD800-\\uDBFF]|^)[\\uDC00-\\uDFFF]'
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regenerate()
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.addRange(0x000000, 0x10FFFF) // add all Unicode code points
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.removeRange(0x0041, 0x007A) // remove all code points from U+0041 to U+007A
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.toString();
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// → '[\\0-@\\{-\\uD7FF\\uE000-\\uFFFF]|[\\uD800-\\uDBFF][\\uDC00-\\uDFFF]|[\\uD800-\\uDBFF](?![\\uDC00-\\uDFFF])|(?:[^\\uD800-\\uDBFF]|^)[\\uDC00-\\uDFFF]'
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```
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### `regenerate.prototype.intersection(codePoints)`
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Removes any code points from the set that are not present in both the set and the given `codePoints` array. `codePoints` must be an array of numeric code point values, i.e. numbers.
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```js
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regenerate()
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.addRange(0x00, 0xFF) // add extended ASCII code points
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.intersection([0x61, 0x69]) // remove all code points from the set except for these
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.toString();
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// → '[ai]'
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```
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Instead of the `codePoints` array, it’s also possible to pass in a Regenerate instance.
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```js
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var whitelist = regenerate(0x61, 0x69);
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regenerate()
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.addRange(0x00, 0xFF) // add extended ASCII code points
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.intersection(whitelist) // remove all code points from the set except for those in the `whitelist` set
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.toString();
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// → '[ai]'
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```
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### `regenerate.prototype.contains(value)`
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Returns `true` if the given value is part of the set, and `false` otherwise. Both code points (numbers) and symbols (strings consisting of a single Unicode symbol) are accepted.
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```js
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var set = regenerate().addRange(0x00, 0xFF);
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set.contains('A');
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// → true
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set.contains(0x1D306);
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// → false
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```
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### `regenerate.prototype.clone()`
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Returns a clone of the current code point set. Any actions performed on the clone won’t mutate the original set.
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```js
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var setA = regenerate(0x1D306);
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var setB = setA.clone().add(0x1F4A9);
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setA.toArray();
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// → [0x1D306]
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setB.toArray();
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// → [0x1D306, 0x1F4A9]
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```
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### `regenerate.prototype.toString(options)`
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Returns a string representing (part of) a regular expression that matches all the symbols mapped to the code points within the set.
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```js
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regenerate(0x1D306, 0x1F4A9).toString();
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// → '\\uD834\\uDF06|\\uD83D\\uDCA9'
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```
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If the `bmpOnly` property of the optional `options` object is set to `true`, the output matches surrogates individually, regardless of whether they’re lone surrogates or just part of a surrogate pair. This simplifies the output, but it can only be used in case you’re certain the strings it will be used on don’t contain any astral symbols.
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```js
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var highSurrogates = regenerate().addRange(0xD800, 0xDBFF);
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highSurrogates.toString();
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// → '[\\uD800-\\uDBFF](?![\\uDC00-\\uDFFF])'
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highSurrogates.toString({ 'bmpOnly': true });
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// → '[\\uD800-\\uDBFF]'
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var lowSurrogates = regenerate().addRange(0xDC00, 0xDFFF);
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lowSurrogates.toString();
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// → '(?:[^\\uD800-\\uDBFF]|^)[\\uDC00-\\uDFFF]'
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lowSurrogates.toString({ 'bmpOnly': true });
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// → '[\\uDC00-\\uDFFF]'
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```
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Note that lone low surrogates cannot be matched accurately using regular expressions in JavaScript. Regenerate’s output makes a best-effort approach but [there can be false negatives in this regard](https://github.com/mathiasbynens/regenerate/issues/28#issuecomment-72224808).
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If the `hasUnicodeFlag` property of the optional `options` object is set to `true`, the output makes use of Unicode code point escapes (`\u{…}`) where applicable. This simplifies the output at the cost of compatibility and portability, since it means the output can only be used as a pattern in a regular expression with [the ES6 `u` flag](https://mathiasbynens.be/notes/es6-unicode-regex) enabled.
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```js
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var set = regenerate().addRange(0x0, 0x10FFFF);
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set.toString();
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// → '[\\0-\\uD7FF\\uE000-\\uFFFF]|[\\uD800-\\uDBFF][\\uDC00-\\uDFFF]|[\\uD800-\\uDBFF](?![\\uDC00-\\uDFFF])|(?:[^\\uD800-\\uDBFF]|^)[\\uDC00-\\uDFFF]''
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set.toString({ 'hasUnicodeFlag': true });
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// → '[\\0-\\u{10FFFF}]'
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```
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### `regenerate.prototype.toRegExp(flags = '')`
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Returns a regular expression that matches all the symbols mapped to the code points within the set. Optionally, you can pass [flags](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp#Parameters) to be added to the regular expression.
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```js
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var regex = regenerate(0x1D306, 0x1F4A9).toRegExp();
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// → /\uD834\uDF06|\uD83D\uDCA9/
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regex.test('𝌆');
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// → true
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regex.test('A');
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// → false
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// With flags:
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var regex = regenerate(0x1D306, 0x1F4A9).toRegExp('g');
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// → /\uD834\uDF06|\uD83D\uDCA9/g
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```
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**Note:** This probably shouldn’t be used. Regenerate is intended as a tool that is used as part of a build process, not at runtime.
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### `regenerate.prototype.valueOf()` or `regenerate.prototype.toArray()`
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Returns a sorted array of unique code points in the set.
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```js
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regenerate(0x1D306)
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.addRange(0x60, 0x65)
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.add(0x59, 0x60) // note: 0x59 is added after 0x65, and 0x60 is a duplicate
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.valueOf();
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// → [0x59, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x1D306]
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```
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### `regenerate.version`
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A string representing the semantic version number.
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## Combine Regenerate with other libraries
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Regenerate gets even better when combined with other libraries such as [Punycode.js](https://mths.be/punycode). Here’s an example where [Punycode.js](https://mths.be/punycode) is used to convert a string into an array of code points, that is then passed on to Regenerate:
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```js
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var regenerate = require('regenerate');
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var punycode = require('punycode');
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var string = 'Lorem ipsum dolor sit amet.';
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// Get an array of all code points used in the string:
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var codePoints = punycode.ucs2.decode(string);
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// Generate a regular expression that matches any of the symbols used in the string:
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regenerate(codePoints).toString();
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// → '[ \\.Ladeilmopr-u]'
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```
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In ES6 you can do something similar with [`Array.from`](https://mths.be/array-from) which uses [the string’s iterator](https://mathiasbynens.be/notes/javascript-unicode#iterating-over-symbols) to split the given string into an array of strings that each contain a single symbol. [`regenerate()`](#regenerateprototypeaddvalue1-value2-value3-) accepts both strings and code points, remember?
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```js
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var regenerate = require('regenerate');
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var string = 'Lorem ipsum dolor sit amet.';
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// Get an array of all symbols used in the string:
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var symbols = Array.from(string);
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// Generate a regular expression that matches any of the symbols used in the string:
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regenerate(symbols).toString();
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// → '[ \\.Ladeilmopr-u]'
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```
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## Support
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Regenerate supports at least Chrome 27+, Firefox 3+, Safari 4+, Opera 10+, IE 6+, Node.js v0.10.0+, io.js v1.0.0+, Narwhal 0.3.2+, RingoJS 0.8+, PhantomJS 1.9.0+, and Rhino 1.7RC4+.
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## Unit tests & code coverage
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After cloning this repository, run `npm install` to install the dependencies needed for Regenerate development and testing. You may want to install Istanbul _globally_ using `npm install istanbul -g`.
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Once that’s done, you can run the unit tests in Node using `npm test` or `node tests/tests.js`. To run the tests in Rhino, Ringo, Narwhal, and web browsers as well, use `grunt test`.
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To generate the code coverage report, use `grunt cover`.
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## Author
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| [](https://twitter.com/mathias "Follow @mathias on Twitter") |
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| [Mathias Bynens](https://mathiasbynens.be/) |
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## License
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Regenerate is available under the [MIT](https://mths.be/mit) license.
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