Chess clock web app.

Online at https://chess-clock.netlify.com

Features

• Three modes - Standard, Hourglass and Countdown.
• Select time limit for each player.
• Time remaining is shown on each half.
• Tap/click your half to switch countdown to other player.
• Pause and cancel buttons.
• Switch display orientation option.
• PWA attributes (add to homescreen, works offline)

Todo

• Use React Router and remove custom push/popstate behaviour.
• Improve style of settings screen.
• Add 'Add to homescreen' button and event to settings screen.
• Check SetState timing - does it need to run (and therefore render) every 100 milliseconds? Can I reduce computation in render function? Maybe extract render stuff to 'Half' component, as this is the bit that will need it?
• Add indication that time input is swipeable on mobile - (e.g. display up down arrow)
• Add small button on timeset to copy time from one to other to make times the same

Modes

1. Standard
   Each player has a finite amount of time which decreases when it is their turn to move.

2. Hourglass
   Each player has time which decreases when it is their turn but increases when it is the other player's turn.

3. Countdown
   Each player has a finite amount of time to move which is reset each move