Parse human readable time in minutes and seconds

parseHumanTime.js

function parseHumanTime(string) {
  const units = {
    'm': 'minutes',
    'min': 'minutes',
    'mins': 'minutes',
    'minutes': 'minutes',
    's': 'seconds',
    'sec': 'seconds',
    'secs': 'seconds',
    'seconds': 'seconds'
  };
  const numbers = [];
  const letters = [];

  string.split('').forEach(char => {
    if ( char === ' ' ) return;

    if ( isNaN(parseInt(char)) ) {
      letters.push(char);
      return;
    }

    if ( letters.length === 0 ) {
      numbers.push(char);
      return;
    }

    const error = new Error('Invalid time. Format is not recognizable.');
    error.name = 'INVALID_TIME_FORMAT';
    throw error;
  });

  const number = parseInt(numbers.join(''));
  const letter = letters.join('');

  const unit = units[letter];

  if ( !unit ) {
    const error = new Error('Invalid time. Can not recognize unit.');
    error.name = 'INVALID_TIME_UNIT';
    throw error;
  }

  return {
    number,
    unit
  }
}