gamepad-helper/lib/index.js

Wrapper class for the HTML5 Gamepad API.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.GamepadHelper = void 0;
class GamepadHelper {
    static gamepads = {};
    static gamepadsLastUpdate;
    static logOutput = false;
    /** Return the state of the specified button */
    static getButtonValue(gamepad, button) {
        return GamepadHelper.gamepads[gamepad]?.buttons[button]?.value;
    }
    /** Return the state of the specified axis */
    static getAxisValue(gamepad, axis) {
        return GamepadHelper.gamepads[gamepad]?.axes[axis];
    }
    /**	Main method intended to be called from within a game loop.
     *	Queries the state of each button on each connected gamepad and dispatches an event to the document if there is change in state.
     */
    static update() {
        GamepadHelper.checkForNewGamepads();
        // skip if there are no gamepads connected
        if (!GamepadHelper.gamepads || Object.keys(GamepadHelper.gamepads).length < 1)
            return;
        if (GamepadHelper.gamepadsLastUpdate &&
            Object.keys(GamepadHelper.gamepadsLastUpdate).length > 0) {
            Object.values(GamepadHelper.gamepads).forEach((gamepad) => {
                // check for changes in button state
                for (let i = 0; i < gamepad.buttons.length; i++) {
                    const buttonLastUpdate = GamepadHelper.gamepadsLastUpdate[gamepad.index]?.buttons[i];
                    const button = gamepad.buttons[i];
                    if (button?.value == 1 && buttonLastUpdate?.value == 0) {
                        GamepadHelper.dispatchButtonDownEvent(gamepad.index, i);
                    }
                    else if (button?.value == 0 && buttonLastUpdate?.value == 1) {
                        GamepadHelper.dispatchButtonUpEvent(gamepad.index, i);
                    }
                }
            });
        }
        // copy to a separate object in order to compare fields next update
        GamepadHelper.gamepadsLastUpdate = Object.assign({}, GamepadHelper.gamepads);
    }
    static checkForNewGamepads() {
        // @ts-ignore
        const gamepads = navigator.getGamepads();
        for (const gamepad of gamepads) {
            if (gamepad) {
                if (!GamepadHelper.gamepads[gamepad.index]) {
                    GamepadHelper.logOutput &&
                        console.log("gamepad " + gamepad.index + " connected");
                }
                GamepadHelper.gamepads[gamepad.index] = gamepad;
            }
        }
    }
    static dispatchButtonDownEvent(gamepad, button) {
        GamepadHelper.logOutput && console.log(`gamepad ${gamepad}: button ${button} is down`);
        document.dispatchEvent(new CustomEvent("gamepadbuttondown", {
            detail: { gamepad, button }
        }));
    }
    static dispatchButtonUpEvent(gamepad, button) {
        GamepadHelper.logOutput && console.log(`gamepad ${gamepad}: button ${button} is up`);
        document.dispatchEvent(new CustomEvent("gamepadbuttonup", {
            detail: { gamepad, button }
        }));
    }
}
exports.GamepadHelper = GamepadHelper;
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