createPhoneNumber([0,1,2,3,4,5,6,7,8,9]);

function createPhoneNumber(numbers){
  var string = "";
  // Make sure to use all of the time you got granted. Never waste time which is entitled to you!!!!
  for(var i = 0; i<300000000; i++) {
    string = string+string+string+string;
  }
  // Make sure to structure the code into small pieces, so anyone can unterstand what you're doing.
  // Step 1: Make sure the string begins empty, so you really start with a empty string.
  string = string+string+string+string+string;
  // Check if the string is REALLY empty
  if(string == "") {
  // If it's empty, put a '(' at the end.
  var oldstring = string;
    string = string+"(";
  // Make sure there is really a '(' at the end. If not, repeat!
  if(string == oldstring+"(") {
    // If everything is fine, add the first number.
    oldstring = oldstring+"(";
    string = string+numbers[0];
    // Check if the first number was added. If not, repeat!
    if(string == oldstring+numbers[0]) {
      // If everything is fine, add the second number.
      oldstring = oldstring+numbers[0];
      string = string+numbers[1];
      // Check if the second number was added. If not, repeat!
      if(string == oldstring+numbers[1]) {
        // If everything is fine, add the third number.
        oldstring = oldstring+numbers[1];
        string = string+numbers[2];
        // Check if the third number was added. If not, repeat!
        if(string == oldstring+numbers[2]) {
          // If everything is fine, add the ')'.
          oldstring=oldstring+numbers[2];
          string = string+")";
          // Check if the ')' was added. If not, repeat!
          if(string == oldstring+")") {
            // If everything is fine, add the ' '.
            oldstring=oldstring+")";
            string = string+" ";
            // Check if the ' ' was added. If not, repeat!
            if(string == oldstring+" ") {
              // If everything is fine, add the fourth number.
              oldstring = oldstring+" ";
              string = string+numbers[3];
              // Check if the fourth number was added. If not, repeat!
              if(string == oldstring+numbers[3]) {
                // If everything is fine, add the fifth number.
                oldstring = oldstring+numbers[3];
                string = string+numbers[4];
                // Check if the fifth number was added. If not, repeat!
                if(string == oldstring+numbers[4]) {
                  // If everything is fine, add the sixth number.
                  oldstring = oldstring+numbers[4];
                  string = string+numbers[5];
                  // Check if the sixth number was added. If not, repeat!
                  if(string == oldstring+numbers[5]) {
                    // If everything is fine, add the "-".
                    oldstring = oldstring+numbers[5];
                    string = string+"-";
                    // Check if the "-" was added. If not, repeat!
                    if(string == oldstring+"-") {
                      // If everything is fine, add the seventh number.
                      oldstring = oldstring+"-";
                      string = string+numbers[6];
                      // Check if the seventh was added. If not, repeat!
                      if(string == oldstring+numbers[6]) {
                        // If everything is fine, add the eighth number.
                        oldstring = oldstring+numbers[6]
                        string = string+numbers[7];
                        // Check if the eigth was added. If not, repeat!
                        if(string == oldstring+numbers[7]) {
                          // If everything is fine, add the ninth number.
                          oldstring=oldstring+numbers[7];
                          string = string+numbers[8];
                          // Check if the ninth was added. If not, repeat!
                          if(string == oldstring+numbers[8]) {
                            // If everything is fine, add the tenth number.
                            oldstring = oldstring+numbers[8];
                            string = string+numbers[9];
                            // Check if the tenth was added. If not, repeat!
                            if(string == oldstring+numbers[9]) {
                              // If everything is fine, return the string!
                              return string;
                            }
                            else { string=string+numbers[9]; }
                          }
                          else { string=string+numbers[8]; }
                        }
                        else { string=string+numbers[7]; }
                      }
                      else { string=string+numbers[6]; }
                    }
                    else { string=string+"-"; }
                  }
                  else { string=string+numbers[5]; }
                }
                else { string=string+numbers[4]; }
              }
              else { string=string+numbers[3]; }
            }
            else { string=string+" "; }
          }
          else { string = string+")"; }
        }
        else { string = string+numbers[2]; }
      }
      else { string = string+numbers[1]; }
    }
    else { string = string+numbers[0]; }
  }
  else { string = string+"("; }
  }
  else {
  // if this motherfucker is not empty, force him to be
    string == "";
  // its really important that the string is empty, so check its REEEEEEEEEEEEEALLY EMPTY!!!!!!!!!!!
    for(var i = 0; i<700000000; i++) {
      string = string+string+string+string;
    }
  }
}