Multiply by 100 by string manipulation, to avoid floating point problems. Mostly for handling currency.

x100.js

function x100(nStr) {
  function replacer(match, p1, p2) {
    return `${`${p1}${p2.padEnd(2, '0').substr(0,2)}`.padStart(1, '0')}.${p2.padEnd(2, '0').substr(2)}`;
  }
  return String(nStr) // just in case
    .replace(/(\d*)\.?(\d*)/, replacer);
}

const tests = [
  '0.00',
  '0.01',
  '0.10',
  '1.00',
  '1.0',
  '1',
  '.01',
  '.1',
  '10.00',
  '10.0',
  '10.',
  '10',
  '10.01',
  '1.265',
  1.265,
  '',
  '0',
  ,
  '1234567890.1234567890'
   ];

tests.forEach((element, index) => {
  const elementx100 = x100(element);
  console.log(`${index+1}: ${element} -> ${elementx100} -> ${Number(elementx100)}`);
});