encode a big integer to base62

Question

I need to create unique referral codes. To make each Referral code unique I am trying to do something like below.

const stringVal = `${currentTimestamp}$         


        

Answer 1

FWIW, the following are two helper functions that convert a BigInt to a desired base and vice versa...

var digits = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';

function bigint2base( x, baseDigits ) {

  let base = BigInt( baseDigits.length );
  let result = '';
  
  while ( 0 < x ) {
    result = baseDigits.charAt( Number( x % base ) ) + result;
    x = x / base;
  }
    
  return result || '0';
  
}


function base2bigint( x, baseDigits ) {

  let base = BigInt( baseDigits.length ); 
  let result = 0n;
  
  for ( let i = 0; i < x.length; i++ ) {
    result = result * base + BigInt( baseDigits.indexOf( x.charAt( i ) ) );
  }
  
  return result;
}

console.log( `BigInt 158632196111710003n to base62 ( '${digits}' )...`);
base62val = bigint2base( 158632196111710003n, digits );
console.log( base62val );

console.log( `Converted back to BigInt is...` );
console.log( base2bigint( base62val, digits ).toString() );

console.log('');
console.log( `BigInt 31957108571341948394931814703184314387417471347093174n to base62 ( '${digits}' )...`);
base62val = bigint2base( 31957108571341948394931814703184314387417471347093174n, digits );
console.log( base62val );

console.log( `Converted back to BigInt is...` );
console.log( base2bigint( base62val, digits ).toString() );

Hope this helps...