Correct Floating Point Math

addDecimals.ts

import { format } from 'util';

export const addDecimals = (...decimals: number[]): number => {
  let total = 0;
  for (const value of decimals) {
    const fixedValue =
      typeof value.toFixed === 'function' ? Number(value.toFixed(2)) : value;
    const addition = (total * 100 + fixedValue * 100) / 100;
    if (Number.isNaN(addition)) {
      throw new Error(
        format(
          'Adding together total: %s and value: %s (typeof %s) resulted in not a number.',
          total,
          fixedValue,
          typeof fixedValue,
        ),
      );
    }
    total = Number(addition.toFixed(2));
  }
  return total;
};