Index: imaps-frontend/node_modules/regenerate/LICENSE-MIT.txt
===================================================================
--- imaps-frontend/node_modules/regenerate/LICENSE-MIT.txt	(revision 79a03170cdde4e801d12257ee86723774970427b)
+++ imaps-frontend/node_modules/regenerate/LICENSE-MIT.txt	(revision 79a03170cdde4e801d12257ee86723774970427b)
@@ -0,0 +1,20 @@
+Copyright Mathias Bynens <https://mathiasbynens.be/>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Index: imaps-frontend/node_modules/regenerate/README.md
===================================================================
--- imaps-frontend/node_modules/regenerate/README.md	(revision 79a03170cdde4e801d12257ee86723774970427b)
+++ imaps-frontend/node_modules/regenerate/README.md	(revision 79a03170cdde4e801d12257ee86723774970427b)
@@ -0,0 +1,338 @@
+# Regenerate [![Build status](https://travis-ci.org/mathiasbynens/regenerate.svg?branch=master)](https://travis-ci.org/mathiasbynens/regenerate) [![Code coverage status](https://img.shields.io/codecov/c/github/mathiasbynens/regenerate.svg)](https://codecov.io/gh/mathiasbynens/regenerate)
+
+_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).)
+
+## Installation
+
+Via [npm](https://npmjs.org/):
+
+```bash
+npm install regenerate
+```
+
+Via [Bower](http://bower.io/):
+
+```bash
+bower install regenerate
+```
+
+In a browser:
+
+```html
+<script src="regenerate.js"></script>
+```
+
+In [Node.js](https://nodejs.org/), [io.js](https://iojs.org/), and [RingoJS ≥ v0.8.0](http://ringojs.org/):
+
+```js
+var regenerate = require('regenerate');
+```
+
+In [Narwhal](http://narwhaljs.org/) and [RingoJS ≤ v0.7.0](http://ringojs.org/):
+
+```js
+var regenerate = require('regenerate').regenerate;
+```
+
+In [Rhino](http://www.mozilla.org/rhino/):
+
+```js
+load('regenerate.js');
+```
+
+Using an AMD loader like [RequireJS](http://requirejs.org/):
+
+```js
+require(
+  {
+    'paths': {
+      'regenerate': 'path/to/regenerate'
+    }
+  },
+  ['regenerate'],
+  function(regenerate) {
+    console.log(regenerate);
+  }
+);
+```
+
+## API
+
+### `regenerate(value1, value2, value3, ...)`
+
+The main Regenerate function. Calling this function creates a new set that gets a chainable API.
+
+```js
+var set = regenerate()
+  .addRange(0x60, 0x69) // add U+0060 to U+0069
+  .remove(0x62, 0x64) // remove U+0062 and U+0064
+  .add(0x1D306); // add U+1D306
+set.valueOf();
+// → [0x60, 0x61, 0x63, 0x65, 0x66, 0x67, 0x68, 0x69, 0x1D306]
+set.toString();
+// → '[`ace-i]|\\uD834\\uDF06'
+set.toRegExp();
+// → /[`ace-i]|\uD834\uDF06/
+```
+
+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.
+
+```js
+regenerate(0x1D306, 'A', '©', 0x2603).toString();
+// → '[A\\xA9\\u2603]|\\uD834\\uDF06'
+
+var items = [0x1D306, 'A', '©', 0x2603];
+regenerate(items).toString();
+// → '[A\\xA9\\u2603]|\\uD834\\uDF06'
+```
+
+### `regenerate.prototype.add(value1, value2, value3, ...)`
+
+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.
+
+```js
+regenerate().add(0x1D306, 'A', '©', 0x2603).toString();
+// → '[A\\xA9\\u2603]|\\uD834\\uDF06'
+
+var items = [0x1D306, 'A', '©', 0x2603];
+regenerate().add(items).toString();
+// → '[A\\xA9\\u2603]|\\uD834\\uDF06'
+```
+
+It’s also possible to pass in a Regenerate instance. Doing so adds all code points in that instance to the current set.
+
+```js
+var set = regenerate(0x1D306, 'A');
+regenerate().add('©', 0x2603).add(set).toString();
+// → '[A\\xA9\\u2603]|\\uD834\\uDF06'
+```
+
+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:
+
+```js
+regenerate(0x1D306, 'A', '©', 0x2603).toString();
+// → '[A\\xA9\\u2603]|\\uD834\\uDF06'
+```
+
+### `regenerate.prototype.remove(value1, value2, value3, ...)`
+
+Any arguments passed to `remove()` are removed from 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.
+
+```js
+regenerate(0x1D306, 'A', '©', 0x2603).remove('☃').toString();
+// → '[A\\xA9]|\\uD834\\uDF06'
+```
+
+It’s also possible to pass in a Regenerate instance. Doing so removes all code points in that instance from the current set.
+
+```js
+var set = regenerate('☃');
+regenerate(0x1D306, 'A', '©', 0x2603).remove(set).toString();
+// → '[A\\xA9]|\\uD834\\uDF06'
+```
+
+### `regenerate.prototype.addRange(start, end)`
+
+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.
+
+```js
+regenerate(0x1D306).addRange(0x00, 0xFF).toString(16);
+// → '[\\0-\\xFF]|\\uD834\\uDF06'
+
+regenerate().addRange('A', 'z').toString();
+// → '[A-z]'
+```
+
+### `regenerate.prototype.removeRange(start, end)`
+
+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.
+
+```js
+regenerate()
+  .addRange(0x000000, 0x10FFFF) // add all Unicode code points
+  .removeRange('A', 'z') // remove all symbols from `A` to `z`
+  .toString();
+// → '[\\0-@\\{-\\uD7FF\\uE000-\\uFFFF]|[\\uD800-\\uDBFF][\\uDC00-\\uDFFF]|[\\uD800-\\uDBFF](?![\\uDC00-\\uDFFF])|(?:[^\\uD800-\\uDBFF]|^)[\\uDC00-\\uDFFF]'
+
+regenerate()
+  .addRange(0x000000, 0x10FFFF) // add all Unicode code points
+  .removeRange(0x0041, 0x007A) // remove all code points from U+0041 to U+007A
+  .toString();
+// → '[\\0-@\\{-\\uD7FF\\uE000-\\uFFFF]|[\\uD800-\\uDBFF][\\uDC00-\\uDFFF]|[\\uD800-\\uDBFF](?![\\uDC00-\\uDFFF])|(?:[^\\uD800-\\uDBFF]|^)[\\uDC00-\\uDFFF]'
+```
+
+### `regenerate.prototype.intersection(codePoints)`
+
+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.
+
+```js
+regenerate()
+  .addRange(0x00, 0xFF) // add extended ASCII code points
+  .intersection([0x61, 0x69]) // remove all code points from the set except for these
+  .toString();
+// → '[ai]'
+```
+
+Instead of the `codePoints` array, it’s also possible to pass in a Regenerate instance.
+
+```js
+var whitelist = regenerate(0x61, 0x69);
+
+regenerate()
+  .addRange(0x00, 0xFF) // add extended ASCII code points
+  .intersection(whitelist) // remove all code points from the set except for those in the `whitelist` set
+  .toString();
+// → '[ai]'
+```
+
+### `regenerate.prototype.contains(value)`
+
+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.
+
+```js
+var set = regenerate().addRange(0x00, 0xFF);
+set.contains('A');
+// → true
+set.contains(0x1D306);
+// → false
+```
+
+### `regenerate.prototype.clone()`
+
+Returns a clone of the current code point set. Any actions performed on the clone won’t mutate the original set.
+
+```js
+var setA = regenerate(0x1D306);
+var setB = setA.clone().add(0x1F4A9);
+setA.toArray();
+// → [0x1D306]
+setB.toArray();
+// → [0x1D306, 0x1F4A9]
+```
+
+### `regenerate.prototype.toString(options)`
+
+Returns a string representing (part of) a regular expression that matches all the symbols mapped to the code points within the set.
+
+```js
+regenerate(0x1D306, 0x1F4A9).toString();
+// → '\\uD834\\uDF06|\\uD83D\\uDCA9'
+```
+
+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.
+
+```js
+var highSurrogates = regenerate().addRange(0xD800, 0xDBFF);
+highSurrogates.toString();
+// → '[\\uD800-\\uDBFF](?![\\uDC00-\\uDFFF])'
+highSurrogates.toString({ 'bmpOnly': true });
+// → '[\\uD800-\\uDBFF]'
+
+var lowSurrogates = regenerate().addRange(0xDC00, 0xDFFF);
+lowSurrogates.toString();
+// → '(?:[^\\uD800-\\uDBFF]|^)[\\uDC00-\\uDFFF]'
+lowSurrogates.toString({ 'bmpOnly': true });
+// → '[\\uDC00-\\uDFFF]'
+```
+
+Note that lone low surrogates cannot be matched accurately using regular expressions in JavaScript without the use of [lookbehind assertions](https://mathiasbynens.be/notes/es-regexp-proposals#lookbehinds), which aren't yet widely supported. 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).
+
+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.
+
+```js
+var set = regenerate().addRange(0x0, 0x10FFFF);
+
+set.toString();
+// → '[\\0-\\uD7FF\\uE000-\\uFFFF]|[\\uD800-\\uDBFF][\\uDC00-\\uDFFF]|[\\uD800-\\uDBFF](?![\\uDC00-\\uDFFF])|(?:[^\\uD800-\\uDBFF]|^)[\\uDC00-\\uDFFF]''
+
+set.toString({ 'hasUnicodeFlag': true });
+// → '[\\0-\\u{10FFFF}]'
+```
+
+### `regenerate.prototype.toRegExp(flags = '')`
+
+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.
+
+```js
+var regex = regenerate(0x1D306, 0x1F4A9).toRegExp();
+// → /\uD834\uDF06|\uD83D\uDCA9/
+regex.test('𝌆');
+// → true
+regex.test('A');
+// → false
+
+// With flags:
+var regex = regenerate(0x1D306, 0x1F4A9).toRegExp('g');
+// → /\uD834\uDF06|\uD83D\uDCA9/g
+```
+
+**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.
+
+### `regenerate.prototype.valueOf()` or `regenerate.prototype.toArray()`
+
+Returns a sorted array of unique code points in the set.
+
+```js
+regenerate(0x1D306)
+  .addRange(0x60, 0x65)
+  .add(0x59, 0x60) // note: 0x59 is added after 0x65, and 0x60 is a duplicate
+  .valueOf();
+// → [0x59, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x1D306]
+```
+
+### `regenerate.version`
+
+A string representing the semantic version number.
+
+## Combine Regenerate with other libraries
+
+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:
+
+```js
+var regenerate = require('regenerate');
+var punycode = require('punycode');
+
+var string = 'Lorem ipsum dolor sit amet.';
+// Get an array of all code points used in the string:
+var codePoints = punycode.ucs2.decode(string);
+
+// Generate a regular expression that matches any of the symbols used in the string:
+regenerate(codePoints).toString();
+// → '[ \\.Ladeilmopr-u]'
+```
+
+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?
+
+```js
+var regenerate = require('regenerate');
+
+var string = 'Lorem ipsum dolor sit amet.';
+// Get an array of all symbols used in the string:
+var symbols = Array.from(string);
+
+// Generate a regular expression that matches any of the symbols used in the string:
+regenerate(symbols).toString();
+// → '[ \\.Ladeilmopr-u]'
+```
+
+## Support
+
+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+.
+
+## Unit tests & code coverage
+
+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`.
+
+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`.
+
+To generate the code coverage report, use `grunt cover`.
+
+## Author
+
+| [![twitter/mathias](https://gravatar.com/avatar/24e08a9ea84deb17ae121074d0f17125?s=70)](https://twitter.com/mathias "Follow @mathias on Twitter") |
+|---|
+| [Mathias Bynens](https://mathiasbynens.be/) |
+
+## License
+
+Regenerate is available under the [MIT](https://mths.be/mit) license.
Index: imaps-frontend/node_modules/regenerate/package.json
===================================================================
--- imaps-frontend/node_modules/regenerate/package.json	(revision 79a03170cdde4e801d12257ee86723774970427b)
+++ imaps-frontend/node_modules/regenerate/package.json	(revision 79a03170cdde4e801d12257ee86723774970427b)
@@ -0,0 +1,38 @@
+{
+  "name": "regenerate",
+  "version": "1.4.2",
+  "description": "Generate JavaScript-compatible regular expressions based on a given set of Unicode symbols or code points.",
+  "homepage": "https://mths.be/regenerate",
+  "main": "regenerate.js",
+  "keywords": [
+    "regex",
+    "regexp",
+    "javascript",
+    "unicode",
+    "generator",
+    "tool"
+  ],
+  "license": "MIT",
+  "author": {
+    "name": "Mathias Bynens",
+    "url": "https://mathiasbynens.be/"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/mathiasbynens/regenerate.git"
+  },
+  "bugs": "https://github.com/mathiasbynens/regenerate/issues",
+  "scripts": {
+    "cover": "istanbul cover --report html --verbose --dir coverage tests/tests.js",
+    "test": "node tests/tests.js"
+  },
+  "devDependencies": {
+    "codecov": "^1.0.1",
+    "grunt": "^0.4.5",
+    "grunt-shell": "^1.1.1",
+    "istanbul": "^0.4.3",
+    "qunit-extras": "^1.1.0",
+    "qunitjs": "~1.11.0",
+    "requirejs": "^2.1.15"
+  }
+}
Index: imaps-frontend/node_modules/regenerate/regenerate.js
===================================================================
--- imaps-frontend/node_modules/regenerate/regenerate.js	(revision 79a03170cdde4e801d12257ee86723774970427b)
+++ imaps-frontend/node_modules/regenerate/regenerate.js	(revision 79a03170cdde4e801d12257ee86723774970427b)
@@ -0,0 +1,1209 @@
+/*! https://mths.be/regenerate v1.4.2 by @mathias | MIT license */
+;(function(root) {
+
+	// Detect free variables `exports`.
+	var freeExports = typeof exports == 'object' && exports;
+
+	// Detect free variable `module`.
+	var freeModule = typeof module == 'object' && module &&
+		module.exports == freeExports && module;
+
+	// Detect free variable `global`, from Node.js/io.js or Browserified code,
+	// and use it as `root`.
+	var freeGlobal = typeof global == 'object' && global;
+	if (freeGlobal.global === freeGlobal || freeGlobal.window === freeGlobal) {
+		root = freeGlobal;
+	}
+
+	/*--------------------------------------------------------------------------*/
+
+	var ERRORS = {
+		'rangeOrder': 'A range\u2019s `stop` value must be greater than or equal ' +
+			'to the `start` value.',
+		'codePointRange': 'Invalid code point value. Code points range from ' +
+			'U+000000 to U+10FFFF.'
+	};
+
+	// https://mathiasbynens.be/notes/javascript-encoding#surrogate-pairs
+	var HIGH_SURROGATE_MIN = 0xD800;
+	var HIGH_SURROGATE_MAX = 0xDBFF;
+	var LOW_SURROGATE_MIN = 0xDC00;
+	var LOW_SURROGATE_MAX = 0xDFFF;
+
+	// In Regenerate output, `\0` is never preceded by `\` because we sort by
+	// code point value, so let’s keep this regular expression simple.
+	var regexNull = /\\x00([^0123456789]|$)/g;
+
+	var object = {};
+	var hasOwnProperty = object.hasOwnProperty;
+	var extend = function(destination, source) {
+		var key;
+		for (key in source) {
+			if (hasOwnProperty.call(source, key)) {
+				destination[key] = source[key];
+			}
+		}
+		return destination;
+	};
+
+	var forEach = function(array, callback) {
+		var index = -1;
+		var length = array.length;
+		while (++index < length) {
+			callback(array[index], index);
+		}
+	};
+
+	var toString = object.toString;
+	var isArray = function(value) {
+		return toString.call(value) == '[object Array]';
+	};
+	var isNumber = function(value) {
+		return typeof value == 'number' ||
+			toString.call(value) == '[object Number]';
+	};
+
+	// This assumes that `number` is a positive integer that `toString()`s nicely
+	// (which is the case for all code point values).
+	var zeroes = '0000';
+	var pad = function(number, totalCharacters) {
+		var string = String(number);
+		return string.length < totalCharacters
+			? (zeroes + string).slice(-totalCharacters)
+			: string;
+	};
+
+	var hex = function(number) {
+		return Number(number).toString(16).toUpperCase();
+	};
+
+	var slice = [].slice;
+
+	/*--------------------------------------------------------------------------*/
+
+	var dataFromCodePoints = function(codePoints) {
+		var index = -1;
+		var length = codePoints.length;
+		var max = length - 1;
+		var result = [];
+		var isStart = true;
+		var tmp;
+		var previous = 0;
+		while (++index < length) {
+			tmp = codePoints[index];
+			if (isStart) {
+				result.push(tmp);
+				previous = tmp;
+				isStart = false;
+			} else {
+				if (tmp == previous + 1) {
+					if (index != max) {
+						previous = tmp;
+						continue;
+					} else {
+						isStart = true;
+						result.push(tmp + 1);
+					}
+				} else {
+					// End the previous range and start a new one.
+					result.push(previous + 1, tmp);
+					previous = tmp;
+				}
+			}
+		}
+		if (!isStart) {
+			result.push(tmp + 1);
+		}
+		return result;
+	};
+
+	var dataRemove = function(data, codePoint) {
+		// Iterate over the data per `(start, end)` pair.
+		var index = 0;
+		var start;
+		var end;
+		var length = data.length;
+		while (index < length) {
+			start = data[index];
+			end = data[index + 1];
+			if (codePoint >= start && codePoint < end) {
+				// Modify this pair.
+				if (codePoint == start) {
+					if (end == start + 1) {
+						// Just remove `start` and `end`.
+						data.splice(index, 2);
+						return data;
+					} else {
+						// Just replace `start` with a new value.
+						data[index] = codePoint + 1;
+						return data;
+					}
+				} else if (codePoint == end - 1) {
+					// Just replace `end` with a new value.
+					data[index + 1] = codePoint;
+					return data;
+				} else {
+					// Replace `[start, end]` with `[startA, endA, startB, endB]`.
+					data.splice(index, 2, start, codePoint, codePoint + 1, end);
+					return data;
+				}
+			}
+			index += 2;
+		}
+		return data;
+	};
+
+	var dataRemoveRange = function(data, rangeStart, rangeEnd) {
+		if (rangeEnd < rangeStart) {
+			throw Error(ERRORS.rangeOrder);
+		}
+		// Iterate over the data per `(start, end)` pair.
+		var index = 0;
+		var start;
+		var end;
+		while (index < data.length) {
+			start = data[index];
+			end = data[index + 1] - 1; // Note: the `- 1` makes `end` inclusive.
+
+			// Exit as soon as no more matching pairs can be found.
+			if (start > rangeEnd) {
+				return data;
+			}
+
+			// Check if this range pair is equal to, or forms a subset of, the range
+			// to be removed.
+			// E.g. we have `[0, 11, 40, 51]` and want to remove 0-10 → `[40, 51]`.
+			// E.g. we have `[40, 51]` and want to remove 0-100 → `[]`.
+			if (rangeStart <= start && rangeEnd >= end) {
+				// Remove this pair.
+				data.splice(index, 2);
+				continue;
+			}
+
+			// Check if both `rangeStart` and `rangeEnd` are within the bounds of
+			// this pair.
+			// E.g. we have `[0, 11]` and want to remove 4-6 → `[0, 4, 7, 11]`.
+			if (rangeStart >= start && rangeEnd < end) {
+				if (rangeStart == start) {
+					// Replace `[start, end]` with `[startB, endB]`.
+					data[index] = rangeEnd + 1;
+					data[index + 1] = end + 1;
+					return data;
+				}
+				// Replace `[start, end]` with `[startA, endA, startB, endB]`.
+				data.splice(index, 2, start, rangeStart, rangeEnd + 1, end + 1);
+				return data;
+			}
+
+			// Check if only `rangeStart` is within the bounds of this pair.
+			// E.g. we have `[0, 11]` and want to remove 4-20 → `[0, 4]`.
+			if (rangeStart >= start && rangeStart <= end) {
+				// Replace `end` with `rangeStart`.
+				data[index + 1] = rangeStart;
+				// Note: we cannot `return` just yet, in case any following pairs still
+				// contain matching code points.
+				// E.g. we have `[0, 11, 14, 31]` and want to remove 4-20
+				// → `[0, 4, 21, 31]`.
+			}
+
+			// Check if only `rangeEnd` is within the bounds of this pair.
+			// E.g. we have `[14, 31]` and want to remove 4-20 → `[21, 31]`.
+			else if (rangeEnd >= start && rangeEnd <= end) {
+				// Just replace `start`.
+				data[index] = rangeEnd + 1;
+				return data;
+			}
+
+			index += 2;
+		}
+		return data;
+	};
+
+	 var dataAdd = function(data, codePoint) {
+		// Iterate over the data per `(start, end)` pair.
+		var index = 0;
+		var start;
+		var end;
+		var lastIndex = null;
+		var length = data.length;
+		if (codePoint < 0x0 || codePoint > 0x10FFFF) {
+			throw RangeError(ERRORS.codePointRange);
+		}
+		while (index < length) {
+			start = data[index];
+			end = data[index + 1];
+
+			// Check if the code point is already in the set.
+			if (codePoint >= start && codePoint < end) {
+				return data;
+			}
+
+			if (codePoint == start - 1) {
+				// Just replace `start` with a new value.
+				data[index] = codePoint;
+				return data;
+			}
+
+			// At this point, if `start` is `greater` than `codePoint`, insert a new
+			// `[start, end]` pair before the current pair, or after the current pair
+			// if there is a known `lastIndex`.
+			if (start > codePoint) {
+				data.splice(
+					lastIndex != null ? lastIndex + 2 : 0,
+					0,
+					codePoint,
+					codePoint + 1
+				);
+				return data;
+			}
+
+			if (codePoint == end) {
+				// Check if adding this code point causes two separate ranges to become
+				// a single range, e.g. `dataAdd([0, 4, 5, 10], 4)` → `[0, 10]`.
+				if (codePoint + 1 == data[index + 2]) {
+					data.splice(index, 4, start, data[index + 3]);
+					return data;
+				}
+				// Else, just replace `end` with a new value.
+				data[index + 1] = codePoint + 1;
+				return data;
+			}
+			lastIndex = index;
+			index += 2;
+		}
+		// The loop has finished; add the new pair to the end of the data set.
+		data.push(codePoint, codePoint + 1);
+		return data;
+	};
+
+	var dataAddData = function(dataA, dataB) {
+		// Iterate over the data per `(start, end)` pair.
+		var index = 0;
+		var start;
+		var end;
+		var data = dataA.slice();
+		var length = dataB.length;
+		while (index < length) {
+			start = dataB[index];
+			end = dataB[index + 1] - 1;
+			if (start == end) {
+				data = dataAdd(data, start);
+			} else {
+				data = dataAddRange(data, start, end);
+			}
+			index += 2;
+		}
+		return data;
+	};
+
+	var dataRemoveData = function(dataA, dataB) {
+		// Iterate over the data per `(start, end)` pair.
+		var index = 0;
+		var start;
+		var end;
+		var data = dataA.slice();
+		var length = dataB.length;
+		while (index < length) {
+			start = dataB[index];
+			end = dataB[index + 1] - 1;
+			if (start == end) {
+				data = dataRemove(data, start);
+			} else {
+				data = dataRemoveRange(data, start, end);
+			}
+			index += 2;
+		}
+		return data;
+	};
+
+	var dataAddRange = function(data, rangeStart, rangeEnd) {
+		if (rangeEnd < rangeStart) {
+			throw Error(ERRORS.rangeOrder);
+		}
+		if (
+			rangeStart < 0x0 || rangeStart > 0x10FFFF ||
+			rangeEnd < 0x0 || rangeEnd > 0x10FFFF
+		) {
+			throw RangeError(ERRORS.codePointRange);
+		}
+		// Iterate over the data per `(start, end)` pair.
+		var index = 0;
+		var start;
+		var end;
+		var added = false;
+		var length = data.length;
+		while (index < length) {
+			start = data[index];
+			end = data[index + 1];
+
+			if (added) {
+				// The range has already been added to the set; at this point, we just
+				// need to get rid of the following ranges in case they overlap.
+
+				// Check if this range can be combined with the previous range.
+				if (start == rangeEnd + 1) {
+					data.splice(index - 1, 2);
+					return data;
+				}
+
+				// Exit as soon as no more possibly overlapping pairs can be found.
+				if (start > rangeEnd) {
+					return data;
+				}
+
+				// E.g. `[0, 11, 12, 16]` and we’ve added 5-15, so we now have
+				// `[0, 16, 12, 16]`. Remove the `12,16` part, as it lies within the
+				// `0,16` range that was previously added.
+				if (start >= rangeStart && start <= rangeEnd) {
+					// `start` lies within the range that was previously added.
+
+					if (end > rangeStart && end - 1 <= rangeEnd) {
+						// `end` lies within the range that was previously added as well,
+						// so remove this pair.
+						data.splice(index, 2);
+						index -= 2;
+						// Note: we cannot `return` just yet, as there may still be other
+						// overlapping pairs.
+					} else {
+						// `start` lies within the range that was previously added, but
+						// `end` doesn’t. E.g. `[0, 11, 12, 31]` and we’ve added 5-15, so
+						// now we have `[0, 16, 12, 31]`. This must be written as `[0, 31]`.
+						// Remove the previously added `end` and the current `start`.
+						data.splice(index - 1, 2);
+						index -= 2;
+					}
+
+					// Note: we cannot return yet.
+				}
+
+			}
+
+			else if (start == rangeEnd + 1 || start == rangeEnd) {
+				data[index] = rangeStart;
+				return data;
+			}
+
+			// Check if a new pair must be inserted *before* the current one.
+			else if (start > rangeEnd) {
+				data.splice(index, 0, rangeStart, rangeEnd + 1);
+				return data;
+			}
+
+			else if (rangeStart >= start && rangeStart < end && rangeEnd + 1 <= end) {
+				// The new range lies entirely within an existing range pair. No action
+				// needed.
+				return data;
+			}
+
+			else if (
+				// E.g. `[0, 11]` and you add 5-15 → `[0, 16]`.
+				(rangeStart >= start && rangeStart < end) ||
+				// E.g. `[0, 3]` and you add 3-6 → `[0, 7]`.
+				end == rangeStart
+			) {
+				// Replace `end` with the new value.
+				data[index + 1] = rangeEnd + 1;
+				// Make sure the next range pair doesn’t overlap, e.g. `[0, 11, 12, 14]`
+				// and you add 5-15 → `[0, 16]`, i.e. remove the `12,14` part.
+				added = true;
+				// Note: we cannot `return` just yet.
+			}
+
+			else if (rangeStart <= start && rangeEnd + 1 >= end) {
+				// The new range is a superset of the old range.
+				data[index] = rangeStart;
+				data[index + 1] = rangeEnd + 1;
+				added = true;
+			}
+
+			index += 2;
+		}
+		// The loop has finished without doing anything; add the new pair to the end
+		// of the data set.
+		if (!added) {
+			data.push(rangeStart, rangeEnd + 1);
+		}
+		return data;
+	};
+
+	var dataContains = function(data, codePoint) {
+		var index = 0;
+		var length = data.length;
+		// Exit early if `codePoint` is not within `data`’s overall range.
+		var start = data[index];
+		var end = data[length - 1];
+		if (length >= 2) {
+			if (codePoint < start || codePoint > end) {
+				return false;
+			}
+		}
+		// Iterate over the data per `(start, end)` pair.
+		while (index < length) {
+			start = data[index];
+			end = data[index + 1];
+			if (codePoint >= start && codePoint < end) {
+				return true;
+			}
+			index += 2;
+		}
+		return false;
+	};
+
+	var dataIntersection = function(data, codePoints) {
+		var index = 0;
+		var length = codePoints.length;
+		var codePoint;
+		var result = [];
+		while (index < length) {
+			codePoint = codePoints[index];
+			if (dataContains(data, codePoint)) {
+				result.push(codePoint);
+			}
+			++index;
+		}
+		return dataFromCodePoints(result);
+	};
+
+	var dataIsEmpty = function(data) {
+		return !data.length;
+	};
+
+	var dataIsSingleton = function(data) {
+		// Check if the set only represents a single code point.
+		return data.length == 2 && data[0] + 1 == data[1];
+	};
+
+	var dataToArray = function(data) {
+		// Iterate over the data per `(start, end)` pair.
+		var index = 0;
+		var start;
+		var end;
+		var result = [];
+		var length = data.length;
+		while (index < length) {
+			start = data[index];
+			end = data[index + 1];
+			while (start < end) {
+				result.push(start);
+				++start;
+			}
+			index += 2;
+		}
+		return result;
+	};
+
+	/*--------------------------------------------------------------------------*/
+
+	// https://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae
+	var floor = Math.floor;
+	var highSurrogate = function(codePoint) {
+		return parseInt(
+			floor((codePoint - 0x10000) / 0x400) + HIGH_SURROGATE_MIN,
+			10
+		);
+	};
+
+	var lowSurrogate = function(codePoint) {
+		return parseInt(
+			(codePoint - 0x10000) % 0x400 + LOW_SURROGATE_MIN,
+			10
+		);
+	};
+
+	var stringFromCharCode = String.fromCharCode;
+	var codePointToString = function(codePoint) {
+		var string;
+		// https://mathiasbynens.be/notes/javascript-escapes#single
+		// Note: the `\b` escape sequence for U+0008 BACKSPACE in strings has a
+		// different meaning in regular expressions (word boundary), so it cannot
+		// be used here.
+		if (codePoint == 0x09) {
+			string = '\\t';
+		}
+		// Note: IE < 9 treats `'\v'` as `'v'`, so avoid using it.
+		// else if (codePoint == 0x0B) {
+		// 	string = '\\v';
+		// }
+		else if (codePoint == 0x0A) {
+			string = '\\n';
+		}
+		else if (codePoint == 0x0C) {
+			string = '\\f';
+		}
+		else if (codePoint == 0x0D) {
+			string = '\\r';
+		}
+		else if (codePoint == 0x2D) {
+			// https://mathiasbynens.be/notes/javascript-escapes#hexadecimal
+			// Note: `-` (U+002D HYPHEN-MINUS) is escaped in this way rather
+			// than by backslash-escaping, in case the output is used outside
+			// of a character class in a `u` RegExp. /\-/u throws, but
+			// /\x2D/u is fine.
+			string = '\\x2D';
+		}
+		else if (codePoint == 0x5C) {
+			string = '\\\\';
+		}
+		else if (
+			codePoint == 0x24 ||
+			(codePoint >= 0x28 && codePoint <= 0x2B) ||
+			codePoint == 0x2E || codePoint == 0x2F ||
+			codePoint == 0x3F ||
+			(codePoint >= 0x5B && codePoint <= 0x5E) ||
+			(codePoint >= 0x7B && codePoint <= 0x7D)
+		) {
+			// The code point maps to an unsafe printable ASCII character;
+			// backslash-escape it. Here’s the list of those symbols:
+			//
+			//     $()*+./?[\]^{|}
+			//
+			// This matches SyntaxCharacters as well as `/` (U+002F SOLIDUS).
+			// https://tc39.github.io/ecma262/#prod-SyntaxCharacter
+			string = '\\' + stringFromCharCode(codePoint);
+		}
+		else if (codePoint >= 0x20 && codePoint <= 0x7E) {
+			// The code point maps to one of these printable ASCII symbols
+			// (including the space character):
+			//
+			//      !"#%&',/0123456789:;<=>@ABCDEFGHIJKLMNO
+			//     PQRSTUVWXYZ_`abcdefghijklmnopqrstuvwxyz~
+			//
+			// These can safely be used directly.
+			string = stringFromCharCode(codePoint);
+		}
+		else if (codePoint <= 0xFF) {
+			string = '\\x' + pad(hex(codePoint), 2);
+		}
+		else { // `codePoint <= 0xFFFF` holds true.
+			// https://mathiasbynens.be/notes/javascript-escapes#unicode
+			string = '\\u' + pad(hex(codePoint), 4);
+		}
+
+		// There’s no need to account for astral symbols / surrogate pairs here,
+		// since `codePointToString` is private and only used for BMP code points.
+		// But if that’s what you need, just add an `else` block with this code:
+		//
+		//     string = '\\u' + pad(hex(highSurrogate(codePoint)), 4)
+		//     	+ '\\u' + pad(hex(lowSurrogate(codePoint)), 4);
+
+		return string;
+	};
+
+	var codePointToStringUnicode = function(codePoint) {
+		if (codePoint <= 0xFFFF) {
+			return codePointToString(codePoint);
+		}
+		return '\\u{' + codePoint.toString(16).toUpperCase() + '}';
+	};
+
+	var symbolToCodePoint = function(symbol) {
+		var length = symbol.length;
+		var first = symbol.charCodeAt(0);
+		var second;
+		if (
+			first >= HIGH_SURROGATE_MIN && first <= HIGH_SURROGATE_MAX &&
+			length > 1 // There is a next code unit.
+		) {
+			// `first` is a high surrogate, and there is a next character. Assume
+			// it’s a low surrogate (else it’s invalid usage of Regenerate anyway).
+			second = symbol.charCodeAt(1);
+			// https://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae
+			return (first - HIGH_SURROGATE_MIN) * 0x400 +
+				second - LOW_SURROGATE_MIN + 0x10000;
+		}
+		return first;
+	};
+
+	var createBMPCharacterClasses = function(data) {
+		// Iterate over the data per `(start, end)` pair.
+		var result = '';
+		var index = 0;
+		var start;
+		var end;
+		var length = data.length;
+		if (dataIsSingleton(data)) {
+			return codePointToString(data[0]);
+		}
+		while (index < length) {
+			start = data[index];
+			end = data[index + 1] - 1; // Note: the `- 1` makes `end` inclusive.
+			if (start == end) {
+				result += codePointToString(start);
+			} else if (start + 1 == end) {
+				result += codePointToString(start) + codePointToString(end);
+			} else {
+				result += codePointToString(start) + '-' + codePointToString(end);
+			}
+			index += 2;
+		}
+		return '[' + result + ']';
+	};
+
+	var createUnicodeCharacterClasses = function(data) {
+		// Iterate over the data per `(start, end)` pair.
+		var result = '';
+		var index = 0;
+		var start;
+		var end;
+		var length = data.length;
+		if (dataIsSingleton(data)) {
+			return codePointToStringUnicode(data[0]);
+		}
+		while (index < length) {
+			start = data[index];
+			end = data[index + 1] - 1; // Note: the `- 1` makes `end` inclusive.
+			if (start == end) {
+				result += codePointToStringUnicode(start);
+			} else if (start + 1 == end) {
+				result += codePointToStringUnicode(start) + codePointToStringUnicode(end);
+			} else {
+				result += codePointToStringUnicode(start) + '-' + codePointToStringUnicode(end);
+			}
+			index += 2;
+		}
+		return '[' + result + ']';
+	};
+
+	var splitAtBMP = function(data) {
+		// Iterate over the data per `(start, end)` pair.
+		var loneHighSurrogates = [];
+		var loneLowSurrogates = [];
+		var bmp = [];
+		var astral = [];
+		var index = 0;
+		var start;
+		var end;
+		var length = data.length;
+		while (index < length) {
+			start = data[index];
+			end = data[index + 1] - 1; // Note: the `- 1` makes `end` inclusive.
+
+			if (start < HIGH_SURROGATE_MIN) {
+
+				// The range starts and ends before the high surrogate range.
+				// E.g. (0, 0x10).
+				if (end < HIGH_SURROGATE_MIN) {
+					bmp.push(start, end + 1);
+				}
+
+				// The range starts before the high surrogate range and ends within it.
+				// E.g. (0, 0xD855).
+				if (end >= HIGH_SURROGATE_MIN && end <= HIGH_SURROGATE_MAX) {
+					bmp.push(start, HIGH_SURROGATE_MIN);
+					loneHighSurrogates.push(HIGH_SURROGATE_MIN, end + 1);
+				}
+
+				// The range starts before the high surrogate range and ends in the low
+				// surrogate range. E.g. (0, 0xDCFF).
+				if (end >= LOW_SURROGATE_MIN && end <= LOW_SURROGATE_MAX) {
+					bmp.push(start, HIGH_SURROGATE_MIN);
+					loneHighSurrogates.push(HIGH_SURROGATE_MIN, HIGH_SURROGATE_MAX + 1);
+					loneLowSurrogates.push(LOW_SURROGATE_MIN, end + 1);
+				}
+
+				// The range starts before the high surrogate range and ends after the
+				// low surrogate range. E.g. (0, 0x10FFFF).
+				if (end > LOW_SURROGATE_MAX) {
+					bmp.push(start, HIGH_SURROGATE_MIN);
+					loneHighSurrogates.push(HIGH_SURROGATE_MIN, HIGH_SURROGATE_MAX + 1);
+					loneLowSurrogates.push(LOW_SURROGATE_MIN, LOW_SURROGATE_MAX + 1);
+					if (end <= 0xFFFF) {
+						bmp.push(LOW_SURROGATE_MAX + 1, end + 1);
+					} else {
+						bmp.push(LOW_SURROGATE_MAX + 1, 0xFFFF + 1);
+						astral.push(0xFFFF + 1, end + 1);
+					}
+				}
+
+			} else if (start >= HIGH_SURROGATE_MIN && start <= HIGH_SURROGATE_MAX) {
+
+				// The range starts and ends in the high surrogate range.
+				// E.g. (0xD855, 0xD866).
+				if (end >= HIGH_SURROGATE_MIN && end <= HIGH_SURROGATE_MAX) {
+					loneHighSurrogates.push(start, end + 1);
+				}
+
+				// The range starts in the high surrogate range and ends in the low
+				// surrogate range. E.g. (0xD855, 0xDCFF).
+				if (end >= LOW_SURROGATE_MIN && end <= LOW_SURROGATE_MAX) {
+					loneHighSurrogates.push(start, HIGH_SURROGATE_MAX + 1);
+					loneLowSurrogates.push(LOW_SURROGATE_MIN, end + 1);
+				}
+
+				// The range starts in the high surrogate range and ends after the low
+				// surrogate range. E.g. (0xD855, 0x10FFFF).
+				if (end > LOW_SURROGATE_MAX) {
+					loneHighSurrogates.push(start, HIGH_SURROGATE_MAX + 1);
+					loneLowSurrogates.push(LOW_SURROGATE_MIN, LOW_SURROGATE_MAX + 1);
+					if (end <= 0xFFFF) {
+						bmp.push(LOW_SURROGATE_MAX + 1, end + 1);
+					} else {
+						bmp.push(LOW_SURROGATE_MAX + 1, 0xFFFF + 1);
+						astral.push(0xFFFF + 1, end + 1);
+					}
+				}
+
+			} else if (start >= LOW_SURROGATE_MIN && start <= LOW_SURROGATE_MAX) {
+
+				// The range starts and ends in the low surrogate range.
+				// E.g. (0xDCFF, 0xDDFF).
+				if (end >= LOW_SURROGATE_MIN && end <= LOW_SURROGATE_MAX) {
+					loneLowSurrogates.push(start, end + 1);
+				}
+
+				// The range starts in the low surrogate range and ends after the low
+				// surrogate range. E.g. (0xDCFF, 0x10FFFF).
+				if (end > LOW_SURROGATE_MAX) {
+					loneLowSurrogates.push(start, LOW_SURROGATE_MAX + 1);
+					if (end <= 0xFFFF) {
+						bmp.push(LOW_SURROGATE_MAX + 1, end + 1);
+					} else {
+						bmp.push(LOW_SURROGATE_MAX + 1, 0xFFFF + 1);
+						astral.push(0xFFFF + 1, end + 1);
+					}
+				}
+
+			} else if (start > LOW_SURROGATE_MAX && start <= 0xFFFF) {
+
+				// The range starts and ends after the low surrogate range.
+				// E.g. (0xFFAA, 0x10FFFF).
+				if (end <= 0xFFFF) {
+					bmp.push(start, end + 1);
+				} else {
+					bmp.push(start, 0xFFFF + 1);
+					astral.push(0xFFFF + 1, end + 1);
+				}
+
+			} else {
+
+				// The range starts and ends in the astral range.
+				astral.push(start, end + 1);
+
+			}
+
+			index += 2;
+		}
+		return {
+			'loneHighSurrogates': loneHighSurrogates,
+			'loneLowSurrogates': loneLowSurrogates,
+			'bmp': bmp,
+			'astral': astral
+		};
+	};
+
+	var optimizeSurrogateMappings = function(surrogateMappings) {
+		var result = [];
+		var tmpLow = [];
+		var addLow = false;
+		var mapping;
+		var nextMapping;
+		var highSurrogates;
+		var lowSurrogates;
+		var nextHighSurrogates;
+		var nextLowSurrogates;
+		var index = -1;
+		var length = surrogateMappings.length;
+		while (++index < length) {
+			mapping = surrogateMappings[index];
+			nextMapping = surrogateMappings[index + 1];
+			if (!nextMapping) {
+				result.push(mapping);
+				continue;
+			}
+			highSurrogates = mapping[0];
+			lowSurrogates = mapping[1];
+			nextHighSurrogates = nextMapping[0];
+			nextLowSurrogates = nextMapping[1];
+
+			// Check for identical high surrogate ranges.
+			tmpLow = lowSurrogates;
+			while (
+				nextHighSurrogates &&
+				highSurrogates[0] == nextHighSurrogates[0] &&
+				highSurrogates[1] == nextHighSurrogates[1]
+			) {
+				// Merge with the next item.
+				if (dataIsSingleton(nextLowSurrogates)) {
+					tmpLow = dataAdd(tmpLow, nextLowSurrogates[0]);
+				} else {
+					tmpLow = dataAddRange(
+						tmpLow,
+						nextLowSurrogates[0],
+						nextLowSurrogates[1] - 1
+					);
+				}
+				++index;
+				mapping = surrogateMappings[index];
+				highSurrogates = mapping[0];
+				lowSurrogates = mapping[1];
+				nextMapping = surrogateMappings[index + 1];
+				nextHighSurrogates = nextMapping && nextMapping[0];
+				nextLowSurrogates = nextMapping && nextMapping[1];
+				addLow = true;
+			}
+			result.push([
+				highSurrogates,
+				addLow ? tmpLow : lowSurrogates
+			]);
+			addLow = false;
+		}
+		return optimizeByLowSurrogates(result);
+	};
+
+	var optimizeByLowSurrogates = function(surrogateMappings) {
+		if (surrogateMappings.length == 1) {
+			return surrogateMappings;
+		}
+		var index = -1;
+		var innerIndex = -1;
+		while (++index < surrogateMappings.length) {
+			var mapping = surrogateMappings[index];
+			var lowSurrogates = mapping[1];
+			var lowSurrogateStart = lowSurrogates[0];
+			var lowSurrogateEnd = lowSurrogates[1];
+			innerIndex = index; // Note: the loop starts at the next index.
+			while (++innerIndex < surrogateMappings.length) {
+				var otherMapping = surrogateMappings[innerIndex];
+				var otherLowSurrogates = otherMapping[1];
+				var otherLowSurrogateStart = otherLowSurrogates[0];
+				var otherLowSurrogateEnd = otherLowSurrogates[1];
+				if (
+					lowSurrogateStart == otherLowSurrogateStart &&
+					lowSurrogateEnd == otherLowSurrogateEnd &&
+					otherLowSurrogates.length === 2
+				) {
+					// Add the code points in the other item to this one.
+					if (dataIsSingleton(otherMapping[0])) {
+						mapping[0] = dataAdd(mapping[0], otherMapping[0][0]);
+					} else {
+						mapping[0] = dataAddRange(
+							mapping[0],
+							otherMapping[0][0],
+							otherMapping[0][1] - 1
+						);
+					}
+					// Remove the other, now redundant, item.
+					surrogateMappings.splice(innerIndex, 1);
+					--innerIndex;
+				}
+			}
+		}
+		return surrogateMappings;
+	};
+
+	var surrogateSet = function(data) {
+		// Exit early if `data` is an empty set.
+		if (!data.length) {
+			return [];
+		}
+
+		// Iterate over the data per `(start, end)` pair.
+		var index = 0;
+		var start;
+		var end;
+		var startHigh;
+		var startLow;
+		var endHigh;
+		var endLow;
+		var surrogateMappings = [];
+		var length = data.length;
+		while (index < length) {
+			start = data[index];
+			end = data[index + 1] - 1;
+
+			startHigh = highSurrogate(start);
+			startLow = lowSurrogate(start);
+			endHigh = highSurrogate(end);
+			endLow = lowSurrogate(end);
+
+			var startsWithLowestLowSurrogate = startLow == LOW_SURROGATE_MIN;
+			var endsWithHighestLowSurrogate = endLow == LOW_SURROGATE_MAX;
+			var complete = false;
+
+			// Append the previous high-surrogate-to-low-surrogate mappings.
+			// Step 1: `(startHigh, startLow)` to `(startHigh, LOW_SURROGATE_MAX)`.
+			if (
+				startHigh == endHigh ||
+				startsWithLowestLowSurrogate && endsWithHighestLowSurrogate
+			) {
+				surrogateMappings.push([
+					[startHigh, endHigh + 1],
+					[startLow, endLow + 1]
+				]);
+				complete = true;
+			} else {
+				surrogateMappings.push([
+					[startHigh, startHigh + 1],
+					[startLow, LOW_SURROGATE_MAX + 1]
+				]);
+			}
+
+			// Step 2: `(startHigh + 1, LOW_SURROGATE_MIN)` to
+			// `(endHigh - 1, LOW_SURROGATE_MAX)`.
+			if (!complete && startHigh + 1 < endHigh) {
+				if (endsWithHighestLowSurrogate) {
+					// Combine step 2 and step 3.
+					surrogateMappings.push([
+						[startHigh + 1, endHigh + 1],
+						[LOW_SURROGATE_MIN, endLow + 1]
+					]);
+					complete = true;
+				} else {
+					surrogateMappings.push([
+						[startHigh + 1, endHigh],
+						[LOW_SURROGATE_MIN, LOW_SURROGATE_MAX + 1]
+					]);
+				}
+			}
+
+			// Step 3. `(endHigh, LOW_SURROGATE_MIN)` to `(endHigh, endLow)`.
+			if (!complete) {
+				surrogateMappings.push([
+					[endHigh, endHigh + 1],
+					[LOW_SURROGATE_MIN, endLow + 1]
+				]);
+			}
+
+			index += 2;
+		}
+
+		// The format of `surrogateMappings` is as follows:
+		//
+		//     [ surrogateMapping1, surrogateMapping2 ]
+		//
+		// i.e.:
+		//
+		//     [
+		//       [ highSurrogates1, lowSurrogates1 ],
+		//       [ highSurrogates2, lowSurrogates2 ]
+		//     ]
+		return optimizeSurrogateMappings(surrogateMappings);
+	};
+
+	var createSurrogateCharacterClasses = function(surrogateMappings) {
+		var result = [];
+		forEach(surrogateMappings, function(surrogateMapping) {
+			var highSurrogates = surrogateMapping[0];
+			var lowSurrogates = surrogateMapping[1];
+			result.push(
+				createBMPCharacterClasses(highSurrogates) +
+				createBMPCharacterClasses(lowSurrogates)
+			);
+		});
+		return result.join('|');
+	};
+
+	var createCharacterClassesFromData = function(data, bmpOnly, hasUnicodeFlag) {
+		if (hasUnicodeFlag) {
+			return createUnicodeCharacterClasses(data);
+		}
+		var result = [];
+
+		var parts = splitAtBMP(data);
+		var loneHighSurrogates = parts.loneHighSurrogates;
+		var loneLowSurrogates = parts.loneLowSurrogates;
+		var bmp = parts.bmp;
+		var astral = parts.astral;
+		var hasLoneHighSurrogates = !dataIsEmpty(loneHighSurrogates);
+		var hasLoneLowSurrogates = !dataIsEmpty(loneLowSurrogates);
+
+		var surrogateMappings = surrogateSet(astral);
+
+		if (bmpOnly) {
+			bmp = dataAddData(bmp, loneHighSurrogates);
+			hasLoneHighSurrogates = false;
+			bmp = dataAddData(bmp, loneLowSurrogates);
+			hasLoneLowSurrogates = false;
+		}
+
+		if (!dataIsEmpty(bmp)) {
+			// The data set contains BMP code points that are not high surrogates
+			// needed for astral code points in the set.
+			result.push(createBMPCharacterClasses(bmp));
+		}
+		if (surrogateMappings.length) {
+			// The data set contains astral code points; append character classes
+			// based on their surrogate pairs.
+			result.push(createSurrogateCharacterClasses(surrogateMappings));
+		}
+		// https://gist.github.com/mathiasbynens/bbe7f870208abcfec860
+		if (hasLoneHighSurrogates) {
+			result.push(
+				createBMPCharacterClasses(loneHighSurrogates) +
+				// Make sure the high surrogates aren’t part of a surrogate pair.
+				'(?![\\uDC00-\\uDFFF])'
+			);
+		}
+		if (hasLoneLowSurrogates) {
+			result.push(
+				// It is not possible to accurately assert the low surrogates aren’t
+				// part of a surrogate pair, since JavaScript regular expressions do
+				// not support lookbehind.
+				'(?:[^\\uD800-\\uDBFF]|^)' +
+				createBMPCharacterClasses(loneLowSurrogates)
+			);
+		}
+		return result.join('|');
+	};
+
+	/*--------------------------------------------------------------------------*/
+
+	// `regenerate` can be used as a constructor (and new methods can be added to
+	// its prototype) but also as a regular function, the latter of which is the
+	// documented and most common usage. For that reason, it’s not capitalized.
+	var regenerate = function(value) {
+		if (arguments.length > 1) {
+			value = slice.call(arguments);
+		}
+		if (this instanceof regenerate) {
+			this.data = [];
+			return value ? this.add(value) : this;
+		}
+		return (new regenerate).add(value);
+	};
+
+	regenerate.version = '1.4.2';
+
+	var proto = regenerate.prototype;
+	extend(proto, {
+		'add': function(value) {
+			var $this = this;
+			if (value == null) {
+				return $this;
+			}
+			if (value instanceof regenerate) {
+				// Allow passing other Regenerate instances.
+				$this.data = dataAddData($this.data, value.data);
+				return $this;
+			}
+			if (arguments.length > 1) {
+				value = slice.call(arguments);
+			}
+			if (isArray(value)) {
+				forEach(value, function(item) {
+					$this.add(item);
+				});
+				return $this;
+			}
+			$this.data = dataAdd(
+				$this.data,
+				isNumber(value) ? value : symbolToCodePoint(value)
+			);
+			return $this;
+		},
+		'remove': function(value) {
+			var $this = this;
+			if (value == null) {
+				return $this;
+			}
+			if (value instanceof regenerate) {
+				// Allow passing other Regenerate instances.
+				$this.data = dataRemoveData($this.data, value.data);
+				return $this;
+			}
+			if (arguments.length > 1) {
+				value = slice.call(arguments);
+			}
+			if (isArray(value)) {
+				forEach(value, function(item) {
+					$this.remove(item);
+				});
+				return $this;
+			}
+			$this.data = dataRemove(
+				$this.data,
+				isNumber(value) ? value : symbolToCodePoint(value)
+			);
+			return $this;
+		},
+		'addRange': function(start, end) {
+			var $this = this;
+			$this.data = dataAddRange($this.data,
+				isNumber(start) ? start : symbolToCodePoint(start),
+				isNumber(end) ? end : symbolToCodePoint(end)
+			);
+			return $this;
+		},
+		'removeRange': function(start, end) {
+			var $this = this;
+			var startCodePoint = isNumber(start) ? start : symbolToCodePoint(start);
+			var endCodePoint = isNumber(end) ? end : symbolToCodePoint(end);
+			$this.data = dataRemoveRange(
+				$this.data,
+				startCodePoint,
+				endCodePoint
+			);
+			return $this;
+		},
+		'intersection': function(argument) {
+			var $this = this;
+			// Allow passing other Regenerate instances.
+			// TODO: Optimize this by writing and using `dataIntersectionData()`.
+			var array = argument instanceof regenerate ?
+				dataToArray(argument.data) :
+				argument;
+			$this.data = dataIntersection($this.data, array);
+			return $this;
+		},
+		'contains': function(codePoint) {
+			return dataContains(
+				this.data,
+				isNumber(codePoint) ? codePoint : symbolToCodePoint(codePoint)
+			);
+		},
+		'clone': function() {
+			var set = new regenerate;
+			set.data = this.data.slice(0);
+			return set;
+		},
+		'toString': function(options) {
+			var result = createCharacterClassesFromData(
+				this.data,
+				options ? options.bmpOnly : false,
+				options ? options.hasUnicodeFlag : false
+			);
+			if (!result) {
+				// For an empty set, return something that can be inserted `/here/` to
+				// form a valid regular expression. Avoid `(?:)` since that matches the
+				// empty string.
+				return '[]';
+			}
+			// Use `\0` instead of `\x00` where possible.
+			return result.replace(regexNull, '\\0$1');
+		},
+		'toRegExp': function(flags) {
+			var pattern = this.toString(
+				flags && flags.indexOf('u') != -1 ?
+					{ 'hasUnicodeFlag': true } :
+					null
+			);
+			return RegExp(pattern, flags || '');
+		},
+		'valueOf': function() { // Note: `valueOf` is aliased as `toArray`.
+			return dataToArray(this.data);
+		}
+	});
+
+	proto.toArray = proto.valueOf;
+
+	// Some AMD build optimizers, like r.js, check for specific condition patterns
+	// like the following:
+	if (
+		typeof define == 'function' &&
+		typeof define.amd == 'object' &&
+		define.amd
+	) {
+		define(function() {
+			return regenerate;
+		});
+	}	else if (freeExports && !freeExports.nodeType) {
+		if (freeModule) { // in Node.js, io.js, or RingoJS v0.8.0+
+			freeModule.exports = regenerate;
+		} else { // in Narwhal or RingoJS v0.7.0-
+			freeExports.regenerate = regenerate;
+		}
+	} else { // in Rhino or a web browser
+		root.regenerate = regenerate;
+	}
+
+}(this));
