About
This is a small game about reading JavaScript. You get a few lines of code and decide what they do, without asking an agent. Then you find out why.
Why
Coding agents write a lot of the code we ship now, and nobody has time to review all of it. Skills you don't use fade: the order things run in, how hoisting works, why 0.1 + 0.2 isn't 0.3. Reading code yourself is how you keep them.
The questions
The 155 questions and their explanations are by Lydia Hallie (opens in a new tab), from javascript-questions (opens in a new tab), with fixes from its many contributors. Every card links back to its original.
This app is open source. To add or fix a question, open a pull request on GitHub (opens in a new tab); the contributing guide (opens in a new tab) shows the format.
Licence
The app's code is MIT licensed. The questions are MIT licensed too and keep their original notice: Copyright (c) 2019 Lydia Hallie.
Privacy
There are no accounts and no cookies. Your answers, your place in the deck and your theme are stored in this browser, on this device, and aren't sent anywhere. So the game works offline, your browser also keeps a copy of the app and the questions. Clearing this site's data removes all of it. To know how many people visit, page views are counted anonymously with Vercel Web Analytics: no cookies, nothing that identifies you, and nothing at all if your browser asks not to be tracked.