Stuck on Mute — JavaScript Bug Hunt

Briefing

Inspired by the most 2020 bug imaginable: you unmute, the app says you're unmuted, everyone still hears silence. Under the hood, rapid toggles were computed against a stale snapshot of the state instead of the latest value.

muteState.js folds mic events. Each toggle must flip the current state.

Bug report

BUG-UNMUTE · Priority: Critical (all-hands demo) · Reported by: everyone

processEvents(initialMuted, events):

• {type:"toggle"} flips the CURRENT state
• {type:"set", muted} assigns directly
• returns the final state

Observed: two quick toggles from unmuted leave you MUTED — both toggles computed against the initial value.

Logs

[mic] start=false toggle toggle -> true (expected false)

The code as shipped

src/av/muteState.js (editable)

// Folds microphone events into the final mute state.
exports.processEvents = function (initialMuted, events) {
  var muted = initialMuted;
  for (var i = 0; i < events.length; i++) {
    var e = events[i];
    if (e.type === "toggle") {
      muted = !initialMuted;
    } else if (e.type === "set") {
      muted = e.muted;
    }
  }
  return muted;
};