TIL #2: tmux, Docker's Architecture, CSS Feature Queries And Lodash.

tmux

In February 2021, I learned about tmux and added it to my workflow. It’s been great so far, with a gentle learning curve. My main problem with it now is that I haven’t been able to find a way to implement scrolling.

When I get a very long stack trace, I have to use a standard terminal window to read through. I lose sessions and windows when I restart my machine; it would be nice if the sessions persisted. I’m yet to learn if that is possible. Other than that, it’s nice to work with tmux.

EDIT: I’ve since learned to persist sessions in tmux. Yay! It turns out there’s a tmux plugin for that. In my .tmux.conf, I had to pop in set -g mouse on.

CSS Feature Queries

I was pretty stoked when I learned about CSS Media Queries. I thought it was fantastic, and it truly is. For a WebRTC app that I’m working on recently, the building process forced me to learn a bit about CSS Grid and Flexbox. Reading documentation led me to discover CSS Feature Queries. It’s a neat feature that’s available in almost all browsers.

Much like Media Queries, Feature Queries let you run CSS conditionally. In the case of Feature Queries, you can check if a browser supports Flexbox. If it does, you run the Flexbox CSS. Otherwise, you load CSS that tries to mimic some Flexbox effects.

Here’s a how you’d use it:

@supports not (display: grid) {
// CSS for older browsers.
}
@supports (display: grid) {
// CSS for newer browsers.
}

Some refer to it as the “@supports rule”. I like the “Feature Queries” name more.

The @supports rule is a conditional group rule whose condition tests whether the user agent supports CSS property:value pairs. W3C

The Architecture of Docker

Docker used the resource features of the Linux kernel to allow containers to run in a Linux instance. It’s more of a Linux product than anything else. I saw some benchmarks running around Twitter about how Rails with Docker development on Macs is slow. Everything makes sense now.

The docker daemon’s native home is a Linux host. If you’re running Docker on any other OS, you’ll pay for the overhead. Docker has to start a Linux virtual machine on a non-Linux host to get things working. For instance, on a Mac, the Docker CLI has to do extra work to forward CLI input to the Docker Daemon.

Lodash

If you write a lot of JavaScript and don’t use Lodash, you’re missing out on a collection of libraries written to keep code modular. I checked out the full suite of Lodash. It has frequently used functions written more concisely, much like how Active Support and Ruby provide ready-made methods to ease programmers’ lives.

For example the raw JavaScript implementation of a function that finds the intersection of two array cannot be prettier than doing it with Lodash:

\_.intersection([2, 1], [2, 3]);
// => [2]

There’s a whole lot more utility functions in the documentation.

I like Lodash more when I discovered that it has a debounce function. I can see how this could come in handy when you’re modifying a page when the viewport is resized. This function only invokes the functions after a given amount of time to save the browser from unnecessary work that could hinder performance.