Inserting a space at a specific index of a string – JavaScript

By using slice() method :

let s = "12:40:22AM";
 
let indexPosition = s.length - 2;

let result = s.slice(0, indexPosition) + " " + s.slice(indexPosition);

console.log(result);

// 12:40:22 AM (space is added before AM)

Explanation :

1. s = "12:40:22AM"
2. indexPosition = 10 - 2 = 8
3. result = 12:40:22 + " " + AM = 12:40:22 AM