Node.js implements searching for a certain string and the file it is located in a directory_node.js

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");
}