Method setPreviouslyAcknowledged

src/server/chat.js:266–268

(lastSeen, lastRejected = {})

  // we need to store it in memory to allow those entries to be approved again without
  // erroring about a message we never sent in the next serverbound message packet we get.
  setPreviouslyAcknowledged (lastSeen, lastRejected = {}) {
    this.lastSeen = lastSeen.map(e => Object.values(e)).push(Object.values(lastRejected))
  }

  previouslyAcknowledged (sender, signature) {
    return this.lastSeen.some(([a, b]) => a === sender && b === signature)