My code working perfectly fine :

const getValueOf=(y)=>{return parseInt('1'.repeat(y),2)};

/*

| Chars   | Binary        | Decimal
| 4       | 1111          | 15

*/

console.log(getValueOf(4)); // = 15

/*

| Chars   | Binary        | Decimal
| 10      | 1111111111    | 1023

*/

console.log(getValueOf(10)); // = 1023

/* -------------- */

console.time('I bet it can be FASTER!');
for(let z=0;z<10000000;++z){getValueOf(10)};
console.timeEnd('I bet it can be FASTER!')

However I feel like covert it to text is a bit sloppy way to solve the issue and I bet there is much faster way to make it work

Your take in 3… 2… 1…