In case you don’t know it, we can use raw strings, like embedding JS code, in hiccup.

I just found out we can use raw to prevent strings from getting escaped. I used to have to define a dedicated app.js for that, which would need an extra HTTP request.

Looking back, I should’ve found this at the very beginning, as it’s just mentioned on its GitHub homepage, but somehow I missed it.

Sometimes, we may want a few examples of a Clojure API for inspiration while developing, especially when reading other people's or open source code.

With Cider in Emacs, we can run M-x cider-doc to see the docstring for the symbol. We can even use M-x cider-clojuredocs for some examples if the symbol is from the language core.

I happened to find this command recently. I bet I was not the only one who didn't know it, thus I'm sharing.

So you're more than excited to find out how Clojure's thread macros can make code clean and concise, you just love it! But at some point you'll be trapped a bit as the threaded argument's positions are inconsistent using -> or ->>.

Luckily, you can use as-> to place the argument wherever you like:

It's amazingly easy to group things in Clojure. The language core provides a group-by function directly. Together with many built-in functions or key functions, it creates a ton of possibilities, and we can also bake our grouping function if none is satisfying.

Example from Clojure Koans.

When you’re building a side project, chances are you need to collect user events so that you can understand user behaviors better and eventually improve your product.

So recently I made a small ClojureScript library for that, it supports web apps or chrome extensions. Check it out at https://github.com/whatacold/google-analytics, it also contains a demo project using shadow-cljs as the build tool.

Hope it helps, and give it a star ⭐ on GitHub and share it if it does, thanks!

In Clojure, we can use comment (aka Rich Comment Blocks) for tests or experiments in development. However, since a comment evaluates to nil, you may run into surprising results or even errors if you misuse it.

In these scenarios, you may tend to use ; to comment them out, but a better choice is to use the discard reader symbol #_.

I was wondering how to construct a multi-key map conditionally while I was coding in Clojure. Ideally, I would like to build it "in one pass" like {:bar 2 (when true :baz 3)}, but from what I had collected from Blue Sky, it seemed that's impossible, or it's just not an idiomatic way to program like that in Clojure. (Or, is this just a side effect of writing too much imperative code?)

Here is the outline for my cider tutorial on YouTube, covering basic things you need to know to get started with cider, and starting exploring the fun of clojure programming with the REPL-driven programming approach.

Recently I've used babashka/fs a little bit, here are some quick notes for it:

• Path vs File. Use Path whenever possible, according to this SO answer to "Java: Path vs File". This is actually Java related.
• It's ok to use a path as a key for a clojure map. At my first try, I somehow came to the conclusion that it's not ok, while I was refactoring the live reload for clay. And later I found that it's totally fine to use it as a key. 😞
• Use fs/path to construct file/directory paths, for example, (fs/path "/tmp" "foo" "bar" "baz.clj") will result in a path object for /tmp/foo/bar/baz.clj on linux. If you're coming from Python, it might remind you of os.path.join(path, *paths).
• Use fs/createdirs for mkdir -p, though its name is a bit misleading, I first thought it's for creating a few dirs.
• fs/with-temp-dir is convenient for creating tests.