Node.js实现在目录中查找某个字符串及所在文件

var path = require("path");
var fs = require("fs");
 
var filePath = process.argv[2];
var lookingForString = process.argv[3];
recursiveReadFile(filePath);
 
function recursiveReadFile(fileName){
 if(!fs.existsSync(fileName)) return;
 if(isFile(fileName)){
  check(fileName);
 }
 if(isDirectory(fileName)){
  var files = fs.readdirSync(fileName);
  files.forEach(function(val,key){
  var temp = path.join(fileName,val);
            if(isDirectory(temp)) recursiveReadFile(temp);
            if (isFile(temp)) check(temp);
  })
 }
}
function check(fileName){
 var data = readFile(fileName);
 var exc = new RegExp(lookingForString);
    if(exc.test(data))
 console.log(fileName);
 
}
function isDirectory(fileName){
    if(fs.existsSync(fileName)) return fs.statSync(fileName).isDirectory();
}
function isFile(fileName){
  if(fs.existsSync(fileName)) return fs.statSync(fileName).isFile();
}
function readFile(fileName){
 if(fs.existsSync(fileName)) return fs.readFileSync(fileName,"utf-8");
}