jellyfish-web/src/components/input/keyboardnavigation.js

/**
 * Module for performing keyboard navigation.
 * @module components/input/keyboardnavigation
 */

import inputManager from "inputManager";
import layoutManager from "layoutManager";

/**
 * Key name mapping.
 */
const KeyNames = {
    13: "Enter",
    19: "Pause",
    27: "Escape",
    32: "Space",
    37: "ArrowLeft",
    38: "ArrowUp",
    39: "ArrowRight",
    40: "ArrowDown",
    // MediaRewind (Tizen/WebOS)
    412: "MediaRewind",
    // MediaStop (Tizen/WebOS)
    413: "MediaStop",
    // MediaPlay (Tizen/WebOS)
    415: "MediaPlay",
    // MediaFastForward (Tizen/WebOS)
    417: "MediaFastForward",
    // Back (WebOS)
    461: "Back",
    // Back (Tizen)
    10009: "Back",
    // MediaTrackPrevious (Tizen)
    10232: "MediaTrackPrevious",
    // MediaTrackNext (Tizen)
    10233: "MediaTrackNext",
    // MediaPlayPause (Tizen)
    10252: "MediaPlayPause"
};

/**
 * Keys used for keyboard navigation.
 */
const NavigationKeys = ["ArrowLeft", "ArrowRight", "ArrowUp", "ArrowDown"];

let hasFieldKey = false;
try {
    hasFieldKey = "key" in new KeyboardEvent("keydown");
} catch (e) {
    console.error("error checking 'key' field");
}

if (!hasFieldKey) {
    // Add [a..z]
    for (let i = 65; i <= 90; i++) {
        KeyNames[i] = String.fromCharCode(i).toLowerCase();
    }
}

/**
 * Returns key name from event.
 *
 * @param {KeyboardEvent} event - keyboard event
 * @return {string} key name
 */
export function getKeyName(event) {
    return KeyNames[event.keyCode] || event.key;
}

/**
 * Returns _true_ if key is used for navigation.
 *
 * @param {string} key - key name
 * @return {boolean} _true_ if key is used for navigation
 */
export function isNavigationKey(key) {
    return NavigationKeys.indexOf(key) != -1;
}

export function enable() {
    document.addEventListener("keydown", function (e) {
        const key = getKeyName(e);

        // Ignore navigation keys for non-TV
        if (!layoutManager.tv && isNavigationKey(key)) {
            return;
        }

        let capture = true;

        switch (key) {
            case "ArrowLeft":
                inputManager.handle("left");
                break;
            case "ArrowUp":
                inputManager.handle("up");
                break;
            case "ArrowRight":
                inputManager.handle("right");
                break;
            case "ArrowDown":
                inputManager.handle("down");
                break;

            case "Back":
                inputManager.handle("back");
                break;

            case "Escape":
                if (layoutManager.tv) {
                    inputManager.handle("back");
                } else {
                    capture = false;
                }
                break;

            case "MediaPlay":
                inputManager.handle("play");
                break;
            case "Pause":
                inputManager.handle("pause");
                break;
            case "MediaPlayPause":
                inputManager.handle("playpause");
                break;
            case "MediaRewind":
                inputManager.handle("rewind");
                break;
            case "MediaFastForward":
                inputManager.handle("fastforward");
                break;
            case "MediaStop":
                inputManager.handle("stop");
                break;
            case "MediaTrackPrevious":
                inputManager.handle("previoustrack");
                break;
            case "MediaTrackNext":
                inputManager.handle("nexttrack");
                break;

            default:
                capture = false;
        }

        if (capture) {
            console.debug("disabling default event handling");
            e.preventDefault();
        }
    });
}

// Gamepad initialisation. No script is required if no gamepads are present at init time, saving a bit of resources.
// Whenever the gamepad is connected, we hand all the control of the gamepad to gamepadtokey.js by removing the event handler
function attachGamepadScript(e) {
    console.log("Gamepad connected! Attaching gamepadtokey.js script");
    window.removeEventListener("gamepadconnected", attachGamepadScript);
    require(["components/input/gamepadtokey"]);
}

// No need to check for gamepads manually at load time, the eventhandler will be fired for that
window.addEventListener("gamepadconnected", attachGamepadScript);

export default {
    enable: enable,
    getKeyName: getKeyName,
    isNavigationKey: isNavigationKey
};