Youtube Music fix volume ratio

Makes the YouTube music volume slider exponential so it's easier to select lower volumes.
换行
// ==UserScript==
// @name         Youtube Music fix volume ratio
// @namespace    http://tampermonkey.net/
// @version      0.4
// @description  Makes the YouTube music volume slider exponential so it's easier to select lower volumes.
// @author       Marco Pfeiffer <[email protected]>
// @icon         https://music.youtube.com/favicon.ico
// @match        https://music.youtube.com/*
// @run-at       document-start
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    // manipulation exponent, higher value = lower volume
    // 3 is the value used by pulseaudio, which Barteks2x figured out this gist here: https://gist.github.com/Barteks2x/a4e189a36a10c159bb1644ffca21c02a
    // 0.05 (or 5%) is the lowest you can select in the UI which with an exponent of 3 becomes 0.000125 or 0.0125%
    const EXPONENT = 3;

    const storedOriginalVolumes = new WeakMap();
    const {get, set} = Object.getOwnPropertyDescriptor(HTMLMediaElement.prototype, 'volume');
    Object.defineProperty(HTMLMediaElement.prototype, 'volume', {
        get () {
            const lowVolume = get.call(this);
            const calculatedOriginalVolume = lowVolume ** (1 / EXPONENT);

            // The calculated value has some accuracy issues which can lead to problems for implementations that expect exact values.
            // To avoid this, I'll store the unmodified volume to return it when read here.
            // This mostly solves the issue, but the initial read has no stored value and the volume can also change though external influences.
            // To avoid ill effects, I check if the stored volume is somewhere in the same range as the calculated volume.
            const storedOriginalVolume = storedOriginalVolumes.get(this);
            const storedDeviation = Math.abs(storedOriginalVolume - calculatedOriginalVolume);

            const originalVolume = storedDeviation < 0.01 ? storedOriginalVolume : calculatedOriginalVolume;
            // console.log('manipulated volume from', lowVolume.toFixed(2), 'to  ', originalVolume.toFixed(2), storedDeviation);
            return originalVolume;
        },
        set (originalVolume) {
            const lowVolume = originalVolume ** EXPONENT;
            storedOriginalVolumes.set(this, originalVolume);
            // console.log('manipulated volume to  ', lowVolume.toFixed(2), 'from', originalVolume.toFixed(2));
            set.call(this, lowVolume);
        }
    });
})();