JS-多關鍵詞列表高亮

/**
 * 多個關鍵詞列表高亮(word_list1,color1,word_list2,color2,...)
 * @param word_list 關鍵詞列表(例: ["關鍵詞a","關鍵詞b"],不區分大小寫)
 * @param color     顏色值(例: "#ff0000")
 * @returns {{render: Function}}
 * 優先順序:word_list1>word_list2>word_list3...
 * @example
 * var highlight = new wordHighlight(["B","C"],"#ff0000",["ABC","DEF"],"blue");
 * console.log(highlight.render("ABC")); // <b style="color:blue">A</b><b style="color:#ff0000">BC</b>
 * console.log(highlight.render("Bc,DEF")); // <b style="color:#ff0000">Bc</b>,<b style="color:blue">DEF</b>
 */
function wordHighlight(word_list,color)
{
    if (!(this instanceof wordHighlight)) {
        throw 'should be called with the new!';
    }
    var that = this;

    that.root        = null;
    that.color_list  = [];
    that.color_range = null;

    var createNode = function(value){
        var node   = {};
        node.value = value || "";
        node.next  = {};
        node.fail  = null;
        node.len   = 0; // word長度，0表示非末尾，非0表示word的長度
        node.color = -1;
        return node;
    }

    var addWord = function(word,color){
        word = word.trim().toLowerCase();
        if (!word) {
            return;
        }
        var cur = that.root;
        var len = word.length;
        for (var i = 0,v; i < len; i++) {
            v = word[i];
            if (cur.next[v] === undefined) {
                node = createNode(v);
                cur.next[v] = node;
            }
            cur = cur.next[v];
        }
        cur.len = len;
        if (cur.color == -1) {
            cur.color = color;
        }
    }

    var buildFailIndex = function(){
        var queue = [];
        var key;
        for (key in that.root.next) {
            that.root.next[key].fail = that.root;
            queue.push(that.root.next[key]);
        }
        while (queue.length) {
            node = queue.shift();
            for (key in node.next) {
                var child_node = node.next[key];
                var val = child_node.value;
                var p = node.fail;
                while (p != null) {
                    if (p.next[val] !== undefined) {
                        child_node.fail = p.next[val];
                        break;
                    }
                    p = p.fail;
                }
                if (p === null) {
                    child_node.fail = that.root;
                }
                queue.push(child_node);
            };
        }
    }

    var mergeRange = function(color,range_list){
        if (!range_list || !range_list.length) {
            return;
        }
        range_list = (function(input_list){
            // 區間合併
            var output_list = [];
            var tmp = {}, left = -1, right = -1;
            input_list.forEach(function(range){
                var start = range[0], end = range[1];
                if (tmp[start] === undefined || tmp[start] < end) {
                    tmp[start] = end;
                }
            });
            for (var start in tmp) {
                var end = tmp[start];
                if (left == -1) {
                    left = 0 | start;
                    right = end;
                }
                if (start > right) {
                    output_list.push([left,right])
                    left = 0 | start;
                    right = end;
                } else if (end > right) {
                    right = end;
                }
            }
            if (left != -1) {
                output_list.push([left, right])
            }
            return output_list;
        })(range_list);
        if (that.color_range === null) {
            that.color_range = {};
            range_list.forEach(function(v){
                that.color_range[v[0]] = [v[1],color];
            });
        } else {
            var xy_list = [0],x,y;
            for (var x in that.color_range) {
                xy_list.push(0|x);
                xy_list.push(that.color_range[x][0]);
            }
            xy_list.push(Infinity);
            //console.log(xy_list);
            var i = 0,len = range_list.length;
            do {
                x = xy_list.shift();
                y = xy_list.shift();
            } while (x == y);
            var _x,_y;
            while (i < len) {
                _x = range_list[i][0];
                _y = range_list[i][1];
                if (y < _y) {
                    if (_x < y) {
                        that.color_range[_x < x ? x : _x] = [y,color];
                    }
                    do {
                        x = xy_list.shift();
                        y = xy_list.shift();
                    } while (x == y);
                    continue;
                }
                if (_y > x) {
                    that.color_range[_x < x ? x : _x] = [_y,color];
                }
                i++;
            }
        }
    }

    that.root = createNode();

    var args = Array.prototype.slice.call(arguments);
    while (args.length) {
        var color = that.color_list.length;
        word_list = args.shift();
        if (!word_list.length) {
            args.shift();
            continue;
        }
        that.color_list.push(args.shift());
        for (var i in word_list) {
            addWord(word_list[i],color);
        }
    }
    buildFailIndex();
    //console.log(that.root);
    return {
        render: function(content){
            if (!that.color_list.length) {
                return content;
            }
            var range_list = [];
            var p = that.root;
            var len = content.length;
            var _content = content.toLowerCase();
            for (var i = 0,val,temp; i < len; i++) {
                val = _content[i];
                while (p.next[val] === undefined && p != that.root) {
                    p = p.fail;
                }
                p = p.next[val] ? p.next[val] : that.root;
                temp = p;
                while (temp != that.root) {
                    if (temp.len) {
                        if (!range_list[temp.color]) {
                            range_list[temp.color] = [];
                        }
                        range_list[temp.color].push([i + 1 - temp.len, i + 1]);
                    }
                    temp = temp.fail;
                }
            }
            for (var color in range_list) {
                //console.log(range_list[color]);
                mergeRange(color,range_list[color]);
            }
            if (that.color_range === null) {
                return content;
            }
            var new_content = '',x = 0,y;
            for (y in that.color_range) {
                new_content += content.substring(x,y);
                x = that.color_range[y][0];
                new_content += '<b style="color:' + that.color_list[that.color_range[y][1]] + '">' + content.substring(y,x) + '</b>';
            }
            new_content += content.substring(x);
            that.color_range = null;
            return new_content;
        }
    }
}