Node.js - Zjišťení, jestli soubory obsahují text

var fs = require("fs");

var neco = "ahoj";

function get_uniq(string, file1, file2, callback){
  fs.readFile(file1, 'utf8', function(err, data1) {
    if (err)
    {
      throw err;
      callback(err);
    }
    else
    {
      i = data1.search(string);
      if(i == -1){
        fs.readFile(file2, 'utf8', function(err, data2) {
          if (err)
          {
            throw err;
            callback(err);
          }
          else
          {
            j = data2.search(string);
            if(j == -1){
              callback(false);
            }
            else
            callback(true);
          }
        });
      }
      else
      callback(false);
    }
  });
}

var neco = "ahoj";
get_uniq(neco, "file1.txt", "file2.txt", function(k){
   if(k == false){              
   console.log("zapsat");
   }
});