Yahoo! UI Library

/**
 * Adds accent-folding highlighters to <code>Y.Highlight</code>.
 *
 * @module highlight
 * @submodule highlight-accentfold
 */

/**
 * @class Highlight
 * @static
 */

var AccentFold = Y.Text.AccentFold,
    Escape     = Y.Escape,

    EMPTY_OBJECT = {},

Highlight = Y.mix(Y.Highlight, {
    // -- Public Static Methods ------------------------------------------------

    /**
     * Accent-folding version of <code>all()</code>.
     *
     * @method allFold
     * @param {String} haystack String to apply highlighting to.
     * @param {String|Array} needles String or array of strings that should be
     *   highlighted.
     * @param {Object} options (optional) Options object, which may contain
     *   zero or more of the following properties:
     *
     * <dl>
     *   <dt>startsWith (Boolean)<dt>
     *   <dd>
     *     By default, needles are highlighted wherever they appear in the
     *     haystack. If <code>startsWith</code> is <code>true</code>, matches
     *     must be anchored to the beginning of the string.
     *   </dd>
     * </dl>
     *
     * @return {String} Escaped and highlighted copy of <em>haystack</em>.
     * @static
     */
    allFold: function (haystack, needles, options) {
        var template = Highlight._TEMPLATE,
            result   = [],
            startPos = 0;

        options = Y.merge({
            // While the highlight regex operates on the accent-folded strings,
            // this replacer will highlight the matched positions in the
            // original string.
            //
            // Note: this implementation doesn't handle multi-character folds,
            // like "æ" -> "ae". Doing so correctly would be prohibitively
            // expensive both in terms of code size and runtime performance, so
            // I've chosen to take the pragmatic route and just not do it at
            // all. This is one of many reasons why accent folding is best done
            // on the server.
            replacer: function (match, p1, foldedNeedle, pos) {
                var len;

                // Ignore matches inside HTML entities.
                if (p1 && !(/\s/).test(foldedNeedle)) {
                    return match;
                }

                len = foldedNeedle.length;

                result.push(haystack.substring(startPos, pos) +
                        template.replace(/\{s\}/g, haystack.substr(pos, len)));

                startPos = pos + len;
            }
        }, options || EMPTY_OBJECT);

        // Run the highlighter on the folded strings. We don't care about the
        // output; our replacer function will build the canonical highlighted
        // string, with original accented characters.
        Highlight.all(AccentFold.fold(haystack), AccentFold.fold(needles),
                options);

        // Tack on the remainder of the haystack that wasn't highlighted, if
        // any.
        if (startPos < haystack.length - 1) {
            result.push(haystack.substr(startPos));
        }

        return result.join('');
    },

    /**
     * Accent-folding version of <code>start()</code>.
     *
     * @method startFold
     * @param {String} haystack String to apply highlighting to.
     * @param {String|Array} needles String or array of strings that should be
     *   highlighted.
     * @return {String} Escaped and highlighted copy of <em>haystack</em>.
     * @static
     */
    startFold: function (haystack, needles) {
        return Highlight.allFold(haystack, needles, {startsWith: true});
    },

    /**
     * Accent-folding version of <code>words()</code>.
     *
     * @method wordsFold
     * @param {String} haystack String to apply highlighting to.
     * @param {String|Array} needles String or array of strings containing words
     *   that should be highlighted. If a string is passed, it will be split
     *   into words; if an array is passed, it is assumed to have already been
     *   split.
     * @return {String} Escaped and highlighted copy of <em>haystack</em>.
     * @static
     */
    wordsFold: function (haystack, needles) {
        var template = Highlight._TEMPLATE;

        return Highlight.words(haystack, AccentFold.fold(needles), {
            mapper: function (word, needles) {
                if (needles.hasOwnProperty(AccentFold.fold(word))) {
                    return template.replace(/\{s\}/g, Escape.html(word));
                }

                return Escape.html(word);
            }
        });
    }
});