mediawiki-extensions-RelatedArticles/resources/ext.relatedArticles.lib/CSS.escape/css.escape.js

/*! https://mths.be/cssescape v1.1.0 by @mathias | MIT license */
;(function(root) {

	if (!root.CSS) {
		root.CSS = {};
	}

	var CSS = root.CSS;

	var InvalidCharacterError = function(message) {
		this.message = message;
	};
	InvalidCharacterError.prototype = new Error;
	InvalidCharacterError.prototype.name = 'InvalidCharacterError';

	if (!CSS.escape) {
		// https://drafts.csswg.org/cssom/#serialize-an-identifier
		CSS.escape = function(value) {
			var string = String(value);
			var length = string.length;
			var index = -1;
			var codeUnit;
			var result = '';
			var firstCodeUnit = string.charCodeAt(0);
			while (++index < length) {
				codeUnit = string.charCodeAt(index);
				// Note: there’s no need to special-case astral symbols, surrogate
				// pairs, or lone surrogates.

				// If the character is NULL (U+0000), then throw an
				// `InvalidCharacterError` exception and terminate these steps.
				if (codeUnit == 0x0000) {
					throw new InvalidCharacterError(
						'Invalid character: the input contains U+0000.'
					);
				}

				if (
					// If the character is in the range [\1-\1F] (U+0001 to U+001F) or is
					// U+007F, […]
					(codeUnit >= 0x0001 && codeUnit <= 0x001F) || codeUnit == 0x007F ||
					// If the character is the first character and is in the range [0-9]
					// (U+0030 to U+0039), […]
					(index == 0 && codeUnit >= 0x0030 && codeUnit <= 0x0039) ||
					// If the character is the second character and is in the range [0-9]
					// (U+0030 to U+0039) and the first character is a `-` (U+002D), […]
					(
						index == 1 &&
						codeUnit >= 0x0030 && codeUnit <= 0x0039 &&
						firstCodeUnit == 0x002D
					)
				) {
					// https://drafts.csswg.org/cssom/#escape-a-character-as-code-point
					result += '\\' + codeUnit.toString(16) + ' ';
					continue;
				}

				if (
					// If the character is the first character and is a `-` (U+002D), and
					// there is no second character, […]
					index == 0 &&
					length == 1 &&
					codeUnit == 0x002D
				) {
					result += '\\' + string.charAt(index);
					continue;
				}

				// If the character is not handled by one of the above rules and is
				// greater than or equal to U+0080, is `-` (U+002D) or `_` (U+005F), or
				// is in one of the ranges [0-9] (U+0030 to U+0039), [A-Z] (U+0041 to
				// U+005A), or [a-z] (U+0061 to U+007A), […]
				if (
					codeUnit >= 0x0080 ||
					codeUnit == 0x002D ||
					codeUnit == 0x005F ||
					codeUnit >= 0x0030 && codeUnit <= 0x0039 ||
					codeUnit >= 0x0041 && codeUnit <= 0x005A ||
					codeUnit >= 0x0061 && codeUnit <= 0x007A
				) {
					// the character itself
					result += string.charAt(index);
					continue;
				}

				// Otherwise, the escaped character.
				// https://drafts.csswg.org/cssom/#escape-a-character
				result += '\\' + string.charAt(index);

			}
			return result;
		};
	}

}(typeof global != 'undefined' ? global : this));