Examples

<ReactTimer
  start={0}
  end={value => value === 30}
  onEnd={value => console.log('ENDED WITH VALUE', value)}
  onTick={value => value + 1}
>
  {time => <div>{time}</div>}
</ReactTimer>

<ReactTimer
  start={30}
  end={value => value < 25}
  onEnd={value => console.log('ENDED WITH VALUE', value)}
  onTick={value => value - 1}
>
  {time => <div>{time}</div>}
</ReactTimer>

<ReactTimer
  start={0}
  end={() => false}
  onEnd={value => console.log('ENDED WITH VALUE', value)}
  onTick={value => value + 1}
>
  {time => <div>{time}</div>}
</ReactTimer>

<ReactTimer
  start={0}
  end={() => false}
  onEnd={value => console.log('ENDED WITH VALUE', value)}
  onTick={value => value + 1}
>
  {() => new Date().toString()}
</ReactTimer>