javascript - How to replace a substring between two indices

Question

I want to replace text between two indices in Javascript, something like:

str = "The Hello World Code!";
str.replaceBetween(4,9,"Hi");
// outputs "The Hi World Code"

The indices and the string are both dynamic.

How could I go about doing this?

Answer 1

There is no such method in JavaScript. But you can always create your own:

String.prototype.replaceBetween = function(start, end, what) {
  return this.substring(0, start) + what + this.substring(end);
};

console.log("The Hello World Code!".replaceBetween(4, 9, "Hi"));