javascriptAsync race conditionMedium

API aggregator dropping responses

Time: 0:00

What it should do

loadAll(ids) should load every id and return all the results as an array, so loadAll([1, 2, 3]) returns [10, 20, 30].

What goes wrong

loadAll([1, 2, 3]) returns 10 — a single number rather than an array of three results.

Hints

This is an async and race conditions bug

A missing await, results in the wrong order, and updates that overwrite each other under load.