nodeJS 获取前端高频词

function getFile(filePath) {
  fs.readFile(filePath, (err, data) => {
    if (err) console.log(err);
    if (data) {
      // data is array buffer, so use toString to transfer to string
      return data.toString();
    }
  });
}

// 获取高频词
function getFrequence(str) {
  // 删除特殊符号(只保留字母数字)
  str = str.replace(/[^A-Za-z0-9\s]/ig, '').replace(/[\n+]/ig, '');
  // 转换成数组
  var arr = str.split(' ');
  var obj = {};
  arr.forEach((item) => {
    let key = item.toLowerCase();
    if (!obj[key]) {
      obj[key] = 1;
    } else {
      obj[key] = obj[key] + 1;
    }
  });
  // 获取出现次数最多的几个情况
  var arr2 = [];
  for (let key in obj) {
    let times = obj[key];
    // 这个参数可以调整(现在统计出现次数超过10次的单词)
    if (times > 10) {
      arr2.push({ times, key });
    }
  }
  arr2.sort((a, b) => a.times > b.times ? -1 : 1);
 
  var arr3 = [];
  arr2.forEach(item => {
    arr3.push(item.key);
    // arr3.push(item.times); 
    // 统计次数需要这个代码，如果仅仅是背单词就不需要这个代码
    arr3.push('\n');
  });
  return arr3.join(' ');
}

function writeFile(str) {
  fs.writeFile('./result.txt', str, function(err){ 
    if (err) {
      console.log('write file error');
    } else {
      console.log('write file success');
    }
  });
}

the 5155 
 to 2361 
 a 1951 
 is 1637 
 and 1384 
 of 1366 
 in 1319 
 that 983 
 an 816 
 this 796

call 177 
 string 176 
 promise 174 
 arrays 172 
 also 171 
 second 169 
 key 165 
 argument 160 
 objects 159 
 result 154 
 any 153 
 functions 148 
 into 147 
 two 146 
 properties 145 
 arguments 142 
 variable 139 
 passed 137 
 syntax 136 
 instance 135 
 inside 134 
 prototype 131