Add plugin to control playback speed like in YouTube (from 0.25 to 2)

plugins/playback-speed/front.js

@@ -0,0 +1,81 @@
+const { watchDOMElement } = require("../../providers/dom-elements");
+const { ElementFromFile, templatePath } = require("../utils");
+
+const slider = ElementFromFile(templatePath(__dirname, "slider.html"));
+
+const MIN_PLAYBACK_SPEED = 0.25;
+const MAX_PLAYBACK_SPEED = 2;
+
+let videoElement;
+let playbackSpeedPercentage = 50; // = Playback speed of 1
+
+const computePlayBackSpeed = () => {
+	if (playbackSpeedPercentage <= 50) {
+		// Slow down video by setting a playback speed between MIN_PLAYBACK_SPEED and 1
+		return (
+			MIN_PLAYBACK_SPEED +
+			((1 - MIN_PLAYBACK_SPEED) / 50) * playbackSpeedPercentage
+		);
+	}
+
+	// Accelerate video by setting a playback speed between 1 and MAX_PLAYBACK_SPEED
+	return 1 + ((MAX_PLAYBACK_SPEED - 1) / 50) * (playbackSpeedPercentage - 50);
+};
+
+const updatePlayBackSpeed = () => {
+	const playbackSpeed = Math.round(computePlayBackSpeed() * 100) / 100;
+
+	if (!videoElement || videoElement.playbackRate === playbackSpeed) {
+		return;
+	}
+
+	videoElement.playbackRate = playbackSpeed;
+
+	const playbackSpeedElement = document.querySelector("#playback-speed-value");
+	if (playbackSpeedElement) {
+		playbackSpeedElement.innerHTML = playbackSpeed;
+	}
+};
+
+module.exports = () => {
+	watchDOMElement(
+		"video",
+		(document) => document.querySelector("video"),
+		(element) => {
+			videoElement = element;
+			updatePlayBackSpeed();
+		}
+	);
+
+	watchDOMElement(
+		"menu",
+		(document) =>
+			document.querySelector("ytmusic-menu-popup-renderer paper-listbox"),
+		(menuElement) => {
+			if (!menuElement.contains(slider)) {
+				menuElement.prepend(slider);
+			}
+
+			const playbackSpeedElement = document.querySelector(
+				"#playback-speed-slider #sliderKnob .slider-knob-inner"
+			);
+
+			const playbackSpeedObserver = new MutationObserver((mutations) => {
+				mutations.forEach(function (mutation) {
+					if (mutation.type == "attributes") {
+						const value = playbackSpeedElement.getAttribute("value");
+						playbackSpeedPercentage = parseInt(value, 10);
+						if (isNaN(playbackSpeedPercentage)) {
+							playbackSpeedPercentage = 50;
+						}
+						updatePlayBackSpeed();
+						return;
+					}
+				});
+			});
+			playbackSpeedObserver.observe(playbackSpeedElement, {
+				attributes: true,
+			});
+		}
+	);
+};