RexExp How to stop with `n` time on replace string

February 22, 2023

Here is my string:

const str = "abc def ghi jkl";

I am looking for a result as : abcdefghi jkl first 2 space removed. But at present with my pattern I could not able to extend to 2 times. it only takes the first space and replaces.

my patten:

const letters = str.replace(/([^a-zA-Z])/,  '',);

How to replace only the required times of space replaced?

my result at present: abcdef ghi jkl

for additional knowledge to learn, how to replace only the last or only the 2 instance from the last as well?

>Solution :

Do not let RegEx take away your modesty, a simple for-loop will suffice:

const str = "abc def ghi jkl";
let letters = str;
for (let i = 0; i < 2; i++) {
  letters = letters.replace(/([^a-zA-Z])/,  '',);
}

console.log(letters)

Regarding your side question, if you need to do the last, then match the RegEx from the back by adding a greedy match group in the front .*, then replace the string with that greedy match group:

const str = "abc def ghi jkl";
let letters = str;
for (let i = 0; i < 2; i++) {
  letters = letters.replace(/(.*)[^a-zA-Z]/, '$1',);
}

console.log(letters)