Javascript to MUTE audio?

Require is a Javascript library that doesnot work in newer browsers or might be added to the core in the newest Storyline updates. So you need to ensure not using it directly.

var appState = require("helpers/appState");
appState.onToggleVolume();//mute

Above the first code years ago. This will not work nowadays anymore.
When you however comment the first line and add DS ( for some Articulate internal stuff ) before appState it works fine.

//var appState = require("helpers/appState");
DS.appState.onToggleVolume();//mute

So in later years someone used a ternary operator ( in fact an if/then check https://www.javascripttutorial.net/javascript-ternary-operator/ ) to check for DS or require availability and this works fine still.

//mute/unmute
// Use the global DS object if it exists, otherwise try require:
var appState = window.DS ? DS.appState : require("helpers/appState");
appState.onToggleVolume();