javascriptAsync race conditionMedium

Delayed function returning undefined

Time: 0:00

What it should do

doubleLater(value) should resolve to double the value after a short delay, so doubleLater(4) gives 8.

What goes wrong

doubleLater(4) returns undefined instead of 8.

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.