gamepad-slide-clicker.d.ts

export declare function gamepadButtonPress(listeners: {
  [button: number]: () => void;
}): Promise<void>;

gamepad-slide-clicker.js

export async function gamepadButtonPress(listeners) {
  const lastStates = [];

  while (true) {
    const gamepads = [...navigator.getGamepads()].filter(Boolean);

    if (gamepads.length === 0) {
      await new Promise((resolve) => {
        addEventListener('gamepadconnected', () => resolve(), { once: true });
      });
      continue;
    }

    await new Promise((r) => requestAnimationFrame(r));

    for (const gamepad of gamepads) {
      const state = gamepad.buttons.map((button) => button.pressed);
      const lastState = lastStates[gamepad.index] || state.map(() => false);

      for (const [buttonIndex, callback] of Object.entries(listeners)) {
        const wasPressed = lastState[buttonIndex];
        const pressed = state[buttonIndex];
        if (pressed && !wasPressed) callback();
      }

      lastStates[gamepad.index] = state;
    }
  }
}

// Example usage:
gamepadButtonPress({
  0: () => presentation.next(),
  3: () => presentation.previous(),
});

I would iterate over the listeners since they should be less than the number of buttons.

for (const [index, callback] of Object.entries(listeners)) {
    const wasPressed = lastState[index];
    const pressed = state[index];
    if (pressed && !wasPressed) callback();
}

@Teiem good point! I guess I was thinking too much about making a generic "buttondown", and forgot that I have access to the listeners.

I updated the code. I guess you could optimise the state storage in a similar way.

in the example usage you cna also pass the function by reference (though i can understand writing it this way for clarification you are passing functions ^^)

@jonnytest1 that depends on how the function is written, and whether it depends on a particular this value. https://web.dev/javascript-this/

If there was a way to detect button release as well, it would cover 90% of gamedev needs that use d-pad for movement :)

@luminarious instead of:

if (pressed && !wasPressed) callback();

It would be:

if (wasPressed && !pressed) callback();