Eat Your Food - Netflix Interruptor

userscript.js

// ==UserScript==
// @name         Remember to eat your food while watching Netflix
// @namespace    https://www.tarikguney.com
// @version      0.1
// @description  Kids watching cartoons on Netflix often forget to eat and chew their food, which drives parents crazy. You need to sit down with them and pause the video and remind them to eat their food. This script will automate that.
// @author       Tarik Guney
// @match        https://www.netflix.com/watch/*
// @icon         https://upload.wikimedia.org/wikipedia/commons/thumb/7/75/Netflix_icon.svg/1200px-Netflix_icon.svg.png
// @grant        none
// ==/UserScript==

(function() {
    'use strict';
    var interruptionInterval = 40000; // 40 seconds
    var pauseTime = 8000; // 8 seconds

    var interruptionIntervalId;
    if(document.readyState === 'ready' || document.readyState === 'complete') {
        console.info("page is ready");
        interruptionIntervalId = startInterruptingNetflix();
    } else {
        document.onreadystatechange = function () {
            if (document.readyState == "complete") {
                console.info("page is ready");
                interruptionIntervalId = startInterruptingNetflix();
            }
        }
    }
    // If moving onto the next video in line, rebind the timer.
    let lastUrl = location.href;
    new MutationObserver(() => {
        const url = location.href;
        if (url !== lastUrl) {
            lastUrl = url;
            onUrlChange();
        }
    }).observe(document, {subtree: true, childList: true});

    async function onUrlChange() {
        console.info("Playing the next video");
        clearInterval(interruptionIntervalId);
        await new Promise(resolve => setTimeout(resolve, pauseTime));
        interruptionIntervalId = startInterruptingNetflix();
    }

    async function startInterruptingNetflix(){
        var mediaPlayer = document.getElementsByTagName("video")[0];
        var maximumRetryBucket = 1000;
        while(mediaPlayer == null && maximumRetryBucket >= 0){
            await new Promise(resolve => setTimeout(resolve, 1000));
            mediaPlayer = document.getElementsByTagName("video")[0];
            maximumRetryBucket--;
        }

        if(mediaPlayer == null){
            console.error("the netflix media player could not be found!");
        }

        console.info("the netflix media player is found");
        return setInterval(function(){
            if(mediaPlayer.readyState >= 2 && mediaPlayer.paused == false){
                mediaPlayer.pause();
                console.info("the media player is paused");
                setTimeout(function(){
                    var actualPlayPromise = mediaPlayer.play();
                    actualPlayPromise.then(_ => {
                        console.info("the media player resumes");
                    });

                },pauseTime);
            }

        },interruptionInterval);
    }
})();