/*!  http://mths.be/jsesc v0.5.0 by @mathias */
;(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 or Browserified code,
	// and use it as `root`
	var freeGlobal = typeof global == 'object' && global;
	if (freeGlobal.global === freeGlobal || freeGlobal.window === freeGlobal) {
		root = freeGlobal;
	}

	/*--------------------------------------------------------------------------*/

	var object = {};
	var hasOwnProperty = object.hasOwnProperty;
	var forOwn = function(object, callback) {
		var key;
		for (key in object) {
			if (hasOwnProperty.call(object, key)) {
				callback(key, object[key]);
			}
		}
	};

	var extend = function(destination, source) {
		if (! source) {
			return destination;
		}
		forOwn(source, function(key, value) {
			destination[key] = value;
		});
		return destination;
	};

	var forEach = function(array, callback) {
		var length = array.length;
		var index = -1;
		while (++index < length) {
			callback(array[index]);
		}
	};

	var toString = object.toString;
	var isArray = function(value) {
		return toString.call(value) == '[object Array]';
	};
	var isObject = function(value) {
		// This is a very simple check, but it’s good enough for what we need. 
		return toString.call(value) == '[object Object]';
	};
	var isString = function(value) {
		return typeof value == 'string' ||
			toString.call(value) == '[object String]';
	};
	var isFunction = function(value) {
		// In a perfect world, the `typeof` check would be sufficient.  However,
		// in Chrome 1–12, `typeof /x/ == 'object'`, and in IE 6–8
		// `typeof alert == 'object'` and similar for other host objects. 
		return typeof value == 'function' ||
			toString.call(value) == '[object Function]';
	};

	/*--------------------------------------------------------------------------*/

	// http://mathiasbynens.be/notes/javascript-escapes#single
	var singleEscapes = {
		'"': '\\"',
		'\'': '\\\'',
		'\\': '\\\\',
		'\b': '\\b',
		'\f': '\\f',
		'\n': '\\n',
		'\r': '\\r',
		'\t': '\\t'
		// `\v` is omitted intentionally, because in IE < 9, '\v' == 'v'. 
		// '\v': '\\x0B'
	};
	var regexSingleEscape = /["'\\\b\f\n\r\t]/;

	var regexDigit = /[0-9]/;
	var regexWhitelist = /[ !# -&\(-\[\]-~]/;

	var jsesc = function(argument, options) {
		// Handle options
		var defaults = {
			'escapeEverything': false,
			'quotes': 'single',
			'wrap': false,
			'es6': false,
			'json': false,
			'compact': true,
			'indent': '\t',
			'__indent__': ''
		};
		var json = options && options.json;
		if (json) {
			defaults.quotes = 'double';
			defaults.wrap = true;
		}
		options = extend(defaults, options);
		if (options.quotes ! = 'single' && options.quotes ! = 'double') {
			options.quotes = 'single';
		}
		var quote = options.quotes == 'double' ? '"' : '\''; 
		var compact = options.compact;
		var indent = options.indent;
		var oldIndent;
		var newLine = compact ? '' : ' \n';
		var result;
		var isEmpty = true;

		if (json && argument && isFunction(argument.toJSON)) {
			argument = argument.toJSON();
		}

		if (! isString(argument)) {
			if (isArray(argument)) {
				result = [];
				options.wrap = true;
				oldIndent = options.__indent__;
				indent += oldIndent;
				options.__indent__ = indent;
				forEach(argument, function(value) {
					isEmpty = false;
					result.push(
						(compact ? '' :  indent) +
						jsesc(value, options)
					);
				});
				if (isEmpty) {
					return '[]';
				}
				return '[' + newLine + result.join(',' + newLine) + newLine +
					(compact ? '' :  oldIndent) + ']';
			} else if (! isObject(argument)) {
				if (json) {
					// For some values (e.g. `undefined`, `function` objects),
					// `JSON.stringify(value)` returns `undefined` (which isn’t valid
					// JSON) instead of `'null'`. 
					return JSON.stringify(argument) || 'null';
				}
				return String(argument);
			} else { // it’s an object
				result = [];
				options.wrap = true;
				oldIndent = options.__indent__;
				indent += oldIndent;
				options.__indent__ = indent;
				forOwn(argument, function(key, value) {
					isEmpty = false;
					result.push(
						(compact ? '' :  indent) +
						jsesc(key, options) + ':' +
						(compact ? '' : ' ')  +
						jsesc(value, options)
					);
				});
				if (isEmpty) {
					return '{}';
				}
				return '{' + newLine + result.join(',' + newLine) + newLine +
					(compact ? '' :  oldIndent) + '}';
			}
		}

		var string = argument;
		// Loop over each code unit in the string and escape it
		var index = -1;
		var length = string.length;
		var first;
		var second;
		var codePoint;
		result = '';
		while (++index < length) {
			var character = string.charAt(index);
			if (options.es6) {
				first = string.charCodeAt(index);
				if ( // check if it’s the start of a surrogate pair
					first >= 0xD800 && first <= 0xDBFF && // high surrogate
					length > index + 1 // there is a next code unit
				) {
					second = string.charCodeAt(index + 1);
					if (second >= 0xDC00 && second <= 0xDFFF) { // low surrogate
						// http://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae
						codePoint = (first - 0xD800) * 0x400 + second - 0xDC00 + 0x10000;
						result += '\\u{' + codePoint.toString(16).toUpperCase() + '}';
						index++;
						continue;
					}
				}
			}
			if (! options.escapeEverything) {
				if (regexWhitelist.test(character)) {
					// It’s a printable ASCII character that is not `"`, `'` or `\`,
					// so don’t escape it. 
					result += character;
					continue;
				}
				if (character == '"') {
					result += quote == character ? '\\"' :  character;
					continue;
				}
				if (character == '\'') {
					result += quote == character ? '\\\'' :  character;
					continue;
				}
			}
			if (
				character == '\0' &&
				! json &&
				! regexDigit.test(string.charAt(index + 1))
			) {
				result += '\\0';
				continue;
			}
			if (regexSingleEscape.test(character)) {
				// no need for a `hasOwnProperty` check here
				result += singleEscapes[character];
				continue;
			}
			var charCode = character.charCodeAt(0);
			var hexadecimal = charCode.toString(16).toUpperCase();
			var longhand = hexadecimal.length > 2 || json;
			var escaped = '\\' + (longhand ? ' u' : 'x') +
				('0000' + hexadecimal).slice(longhand ?  -4 : -2);
			result += escaped;
			continue;
		}
		if (options.wrap) {
			result = quote + result + quote;
		}
		return result;
	};

	jsesc.version = '0.5.0';

	/*--------------------------------------------------------------------------*/

	// 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 jsesc;
		});
	}	else if (freeExports && ! freeExports.nodeType) {
		if (freeModule) { // in Node.js or RingoJS v0.8.0+
			freeModule.exports = jsesc;
		} else { // in Narwhal or RingoJS v0.7.0-
			freeExports.jsesc = jsesc;
		}
	} else { // in Rhino or a web browser
		root.jsesc = jsesc;
	}

}(this));
