Javascript using .replace() at a specific index of the search

Question

Is there a function that can replace a string within a string once at a specific index of the string? Example:

var string1="my text is my text and my big text";
var string2="my";
string1.replaceAt(string2,"your",2);

and the resultant output would be "my text is my text and your big text"

Answer 1

You can do this with a little bit of manipulation, not requiring any regex.

I used this function to fetch the position (index) of another string within a string.

From there, it's as simple as returning a substring from the beginning to the found index, injecting your replacement, and then returning the rest of the string.

function replaceAt(s, subString, replacement, index) {
  const p = s.split(subString, index+1).join(subString);
  return p.length < s.length ? p + replacement + s.slice(p.length + subString.length) : s;
}

console.log(replaceAt("my text is my text and my big text", "my", "your", 2))
console.log(replaceAt("my text is my text and that's all", "my", "your", 2))
console.log(replaceAt("my text is my my my my text", "my", "your", 2))