String.fromCharCode gives no result javaScript

Question

after running code i get no result in window. and i cant find problem result have to be string created from charCode.

function rot13(str) {
  var te = [];
  var i = 0;
  var a = 0;
  var newte = [];

  while (i < str.length) {
    te[i] = str.charCodeAt(i);
    i++;
  }
  while (a != te.length) {
    if (te[a] < 65) {
      newte[a] = te[a] + 13;
    } else
      newte[a] = te[a];
    a++;
  }

  var mystring = String.fromCharCode(newte);


  return mystring;
}

// Change the inputs below to test
rot13("SERR PBQR PNZC");

You do nothing with the returned value - what do you expect? — Andrew Li, Oct 20 '16 at 01:05
`String.fromCharCode(newte);` probably doesn't do what you expect either — Jaromanda X, Oct 20 '16 at 01:07
could you explain me what i miss? i try`ed several different scenarios and i always getting error or nothing — EdenLT, Oct 20 '16 at 01:12
Possible duplicate of [Can I pass an array into fromCharCode](http://stackoverflow.com/questions/9936490/can-i-pass-an-array-into-fromcharcode) — Alexander O'Mara, Oct 20 '16 at 01:14

Steven Schobert · Accepted Answer · 2016-10-20T01:13:02.133

0

The method String.fromCharCode expects you to pass each number as an individual argument. In your code sample, you are passing an array as a single argument, which won't work.

Try using the apply() method instead, which will allow you to pass an array, and it will convert that into multiple individual arguments:

var mystring = String.fromCharCode.apply(null, newte);

edited Oct 20 '16 at 01:13

answered Oct 20 '16 at 01:11

Steven Schobert

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1

`.call` does not take an array in this way, that's `.apply`. – Alexander O'Mara Oct 20 '16 at 01:12
Oops, yeah no you're totally right. Updating answer. – Steven Schobert Oct 20 '16 at 01:12

score 0 · Answer 2 · answered Oct 20 '16 at 01:13

Looks like String.fromCharCode() is not defined to operate on an array.

Try like this:

function rot13(str) {
  var result = "";
  
  for (var i = 0; i < str.length; i++) {
    var charCode = str.charCodeAt(i) + 1;
    
    if (charCode < 65) {
      charCode += 13;
    }
    
    result += String.fromCharCode(charCode);
  }
  
  return result;
}

// Change the inputs below to test
console.log(rot13("SERR PBQR PNZC"));

NOTE: I copied your logic for the character substitution, but it doesn't seem correct.

yea, i found that i do not get result as i expected :) going to work with it more. — EdenLT, Oct 20 '16 at 01:24

String.fromCharCode gives no result javaScript

2 Answers2