How do I replace a character at a particular index in JavaScript?

Question

I have a string, let\'s say Hello world and I need to replace the char at index 3. How can I replace a char by specifying a index?

var str = \"h         


        

Answer 1

If you want to replace characters in string, you should create mutable strings. These are essentially character arrays. You could create a factory:

  function MutableString(str) {
    var result = str.split("");
    result.toString = function() {
      return this.join("");
    }
    return result;
  }

Then you can access the characters and the whole array converts to string when used as string:

  var x = MutableString("Hello");
  x[0] = "B"; // yes, we can alter the character
  x.push("!"); // good performance: no new string is created
  var y = "Hi, "+x; // converted to string: "Hi, Bello!"