I did some experiments about this.

Did not found anything on MDN.

Tried some stuff from stackoverflow and alike.

Can’t find a way to convert scientific notation to bigint properly.

Results of my attempts are below.

I am using example with 25! for this.

```
const bigIntFactorial = (n) => {
let result = BigInt(n);
let mult = result - BigInt(1);
while (mult > 0) {
result *= mult;
mult--;
}
return result;
}
const factorial = (n) => {
let result = n;
let mult = result - 1;
while (mult > 0) {
result *= mult;
mult--;
}
return result;
}
console.log('factorial with bigint usage')
console.log(bigIntFactorial(25))//15511210043330985984000000n
console.log('factorial without bigint usage')
console.log(factorial(25))//1.5511210043330984e+25
console.log('trying to convert scientific notation to bigint -????')
console.log(BigInt(factorial(25)));//15511210043330983907819520n
console.log('---------');
//trying stuff from web
//console.log(BigInt(factorial(25).toLocaleString()))//syntax error (well, that's a string)
//trying to wrap the above into number
//console.log(BigInt(Number(factorial(25).toLocaleString())))//RangeError: The number NaN cannot be converted to
//a BigInt because it is not an integer
//trying params for localestring
console.log(BigInt(factorial(25).toLocaleString('fullwide', { useGrouping: false })))
//in the above something happened, some digits missing - ????
```