Schrödinger's Follower Count — JavaScript Bug Hunt

Briefing

Inspired by the follower counters of large social networks, which read from whichever replica answers first — so refreshing your profile makes the number bounce down and back up. Displayed counters should be monotonic: never show fewer than the user has already seen.

counter.js picks what to display.

Bug report

BUG-BOUNCE · Reported by: creator support (screenshots of "losing" followers)

nextDisplay(previousShown, freshReads):

• take the max of the fresh replica reads
• never display LESS than previousShown (replicas lag; going down is noise)
• returns the new displayed value

Observed: the counter renders whatever the slowest replica said.

Logs

[profile] shown 10,204 -> refresh -> 10,197 -> refresh -> 10,205

The code as shipped

src/social/counter.js (editable)

// Chooses the follower count to display.
exports.nextDisplay = function (previousShown, freshReads) {
  return freshReads[freshReads.length - 1];
};