db-lgtv-focus-engine/event/mutation.js

the Best TV focus engine

export function bindMutationObserver(focus_engine) {
    // 防止重复监听
    if (focus_engine._observer) {
        focus_engine._observer.disconnect();
    }
    // 选择需要观察变动的节点
    const targetNode = document.getElementsByTagName('html')[0]

    // 观察器的配置（需要观察什么变动）
    const config = {
        childList: true,
        subtree: true
    };

    // 当观察到变动时执行的回调函数
    const callback = function (mutationsList) {
        if (focus_engine.dont_render) {
            focus_engine.dont_render = false
            return
        }
        focus_engine.render()
    };

    // 创建一个观察器实例并传入回调函数
    const observer = new MutationObserver(callback);

    // 以上述配置开始观察目标节点
    observer.observe(targetNode, config);

    focus_engine._observer = observer
}

export function unbindMutationObserver(focus_engine) {
    focus_engine._observer.disconnect();
}