Curiosum TILs

Hey! Have you ever wondered about tests running inside the IEx shell? For a long time, I was convinced that it’s not really possible. And as it turns out - that’s not really straightforward. You won’t easily find information about that in the documentation.

Sooner or later you may need to convert a string in Elixir to a camel or snake case. With Macro module (available in Elixir without extra dependency) it's super easy.

There is a common scenario: You'd like to debug your Phoenix app with break!/4 or IEx.pry/0. Everything works fine, until... Phoenix server throws a timeout error statement.

Sometimes you may notice that your website displays an unintended horizontal scrollbar. You may be wondering what is the cause.

Did you know that it's possible to set default value in Javascript object destructuring?

By default in the test env, Phoenix doesn't show Logger.debug/Logger.info outputs in the console.

Sometimes you need to do some database operations at once. A simple example: User-A transfers money to User-B. Updating just one balance at the time creates a risk of data desynchronization. What if the first DB operation goes well but updating the second user’s data fails? Sounds like a hard to catch vulnerability.

Ensuring that GraphQL mutations properly update your Apollo client's cache can be a bit tricky - here's how to manually control that.

Nowadays, with an ever-growing number of web services, we tend to overload Web apps with external resources. As a result, it decreases page load speed and affects SEO score. There is a pretty easy solution for that.

People will tell you it's an antipattern, but what if a library needs you to do this?

In some cases, like for testing purposes, you might want to use an npm package stored on a local machine. Here is how you can do that with one simple command.

With pure function React Components you're not allowed to use lifecycle methods like componentDidMount or componentWillUnmount.