stdnum/src/util/strings/format.ts

Standard Number Validation

/**
 * Format in a standard format, substitue '?' for the input characters in order
 *   eg.
 *   "???-??-????", "99922333" => "999-22-3333"
 */
export function formatPattern(pattern: string, input: string): string {
  const values = input.split('');

  return pattern
    .split('')
    .map(c => {
      if (c === '?') {
        return values.shift();
      }
      return c;
    })
    .join('');
}