JavaScript Navigator getGamepads() Method

const lines = [
  "getGamepads: " +
    (typeof navigator.getGamepads === "function" ? "available" : "missing"),
  "slots: " +
    (typeof navigator.getGamepads === "function"
      ? navigator.getGamepads().length
      : "n/a")
];
console.log(lines.join("\n"));

function listConnectedPads() {
  if (!navigator.getGamepads) return ["getGamepads not supported"];
  const pads = Array.from(navigator.getGamepads()).filter(Boolean);
  if (!pads.length) return ["No active gamepads (press a button on your controller)"];
  return pads.map(
    (gp) =>
      "#" + gp.index + " " + gp.id +
      " | buttons=" + gp.buttons.length +
      " axes=" + gp.axes.length
  );
}

console.log(listConnectedPads().join("\n"));

window.addEventListener("gamepadconnected", (e) => {
  const gp = navigator.getGamepads()[e.gamepad.index];
  console.log(
    "Gamepad connected at index " + gp.index + ": " + gp.id +
    " with " + gp.buttons.length + " buttons, " + gp.axes.length + " axes."
  );
});

console.log("Listening for gamepadconnected — press a button on your pad");

function describeFirstPad() {
  if (!navigator.getGamepads) return "getGamepads not supported";
  const gp = Array.from(navigator.getGamepads()).find(Boolean);
  if (!gp) return "No active gamepad";
  const btn0 = gp.buttons[0];
  return [
    "id: " + gp.id,
    "button0.pressed: " + (btn0 ? btn0.pressed : "n/a"),
    "button0.value: " + (btn0 ? btn0.value : "n/a"),
    "axes: [" + gp.axes.map((a) => a.toFixed(2)).join(", ") + "]"
  ].join("\n");
}

console.log(describeFirstPad());

let frames = 0;

function pollGamepads() {
  frames += 1;
  const pads = navigator.getGamepads
    ? Array.from(navigator.getGamepads()).filter(Boolean)
    : [];
  if (frames <= 3) {
    console.log("frame " + frames + " pads=" + pads.length);
  }
  if (frames < 3) {
    requestAnimationFrame(pollGamepads);
  } else {
    console.log("Stopped demo poll after 3 frames");
  }
}

requestAnimationFrame(pollGamepads);