採用DFA算法實現字庫屏蔽規則

//需要過濾的字庫
let filterWordsArr = '廣告|下載|邀請|邀請碼';
//切割字庫成數組
filterWordsArr = filterWordsArr .slice(1, filterWordsArr.length - 1).split('|');
let filterWords = {};
//處理字符串，將字符串切割使用對象遞歸嵌套存儲
function dealWords(wordObj, insertString) {
    if (insertString && insertString.length > 0) {
        //獲取第一個字符
        let firstWord = insertString[0].toLocaleLowerCase();
        //獲取剩餘字符
        let remainStr = insertString.slice(1, insertString.length);
        if (!wordObj[firstWord]) {
            wordObj[firstWord] = {};
        }
        if (remainStr.length > 0) {
            wordObj[firstWord] = dealWords(wordObj[firstWord], remainStr);
        }
        else {
            wordObj[firstWord].isEnd = true;
        }
        return wordObj;
    }
    return wordObj;
}
filterWordsArr.forEach((e) => {
    dealWords(filterWords, e);
});

/**
 * 提取字符串裏面符合規則的文字，並返回數組，都不符合會返回空數組
 */
function checkStr(str) {
    let result = [];
    let stack = [];
    let rule = filterWords;
    //狀態，true表面傳入字符串符合規則
    for (let i = 0; i < str.length; i++) {
        let ch = str.charAt(i).toLocaleLowerCase();
        let item = rule[ch];
        if (!item) {
            i = i - stack.length;
            stack = [];
            rule = filterWords;
        }
        else if (item.isEnd) {
            stack.push(ch);
            result.push(stack.join(""));
            stack = [];
            rule = filterWords;
        }
        else {
            stack.push(ch);
            rule = item;
        }
    }
    return result;
}

/**
 *
 * @param str    //要替換的字符串
 * @param replaceWords //替換成的字符
 */
function getReplaceWord(str, replaceWords) {
    let replaceStr = '';
    for (let i = 0; i < str.length; i++) {
        replaceStr += replaceWords;
    }
    return replaceStr;
}

/**
 * 將符合過濾規則的字符替換成*號
 * @param str           //傳入要過濾的字符串
 * 如 filterStr('我的邀請碼')  =》 返回   "我的**碼"
 */
function filterStr(str) {
    str = str.toLocaleLowerCase();
    let replaceWord = '*';
    let filterWordList = checkStr(str);
    if (filterWordList && filterWordList.length > 0) {
        filterWordList.forEach(e => {
                let replaceWords = getReplaceWord(e, replaceWord);
                str = str.replace(e, replaceWords);    
        });
    }
    return str;
}