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🥷 Clojure Pro Tip 5: Hiccup Raw

Posted on 2025-05-15 (Last modified on 2025-05-17) | 1 minutes | 76 words

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. Hiccup raw in action 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. [Read More]

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🥷 Clojure Pro Tip 4: Cider ClojureDocs

Posted on 2025-04-29 (Last modified on 2025-05-17) | 1 minutes | 82 words

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. Running M-x cider-clojuredocs I happened to find this command recently. I bet I was not the only one who didn't know it, thus I'm sharing. [Read More]

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🥷 Clojure Pro Tip 3: the Thread-As Macro

Posted on 2025-04-23 (Last modified on 2025-05-17) | 1 minutes | 57 words

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:

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🥷 Clojure Pro Tip 2: group-by

Posted on 2025-04-18 (Last modified on 2025-05-17) | 1 minutes | 47 words

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.

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Collecting Events to Google Analytics using ClojureScript

Posted on 2025-04-11 | 1 minutes | 94 words

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! [Read More]

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🥷 Clojure Pro Tip 1: the Discard Reader Symbol

Posted on 2025-04-05 (Last modified on 2025-05-17) | 1 minutes | 64 words

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 #_.

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Constructing Clojure Maps Conditionally

Posted on 2025-01-05 (Last modified on 2025-02-20) | 1 minutes | 190 words

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? [Read More]

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A Few Quick Notes About babashka/fs

Posted on 2024-12-07 (Last modified on 2024-12-19) | 1 minutes | 149 words

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. [Read More]

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Doing Unit test in Clojure Is Easy

Posted on 2024-11-28 (Last modified on 2025-02-26) | 1 minutes | 165 words

While refactoring the live reload feature of Clay, I realized I'd better break long functions into smaller and functional ones (as many as I can), which is also a common practice in the clojure community. Small pure functions not only are easy to verify on the development process (using a REPL), but also are easy to test. And unit tests are easy to write in clojure, just use deftest from clojure. [Read More]

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Adding Clojure Dependencies from the Command Line

Posted on 2024-11-09 (Last modified on 2024-11-10) | 1 minutes | 84 words

While debugging a live reload issue of Clay a few days ago, I learned from Markus Agwin that we can actually add dependencies on the fly from the command line, just like this: clj -Sdeps "{:deps {org.scicloj/clay {:mvn/version \"2-beta21\"}}}". Even better, we can add dependency from a Git repo and specify the commit hash: clj -Sdeps "{:deps {io.github.scicloj/clay {:git/url \"https://github.com/scicloj/clay.git\" :git/sha \"35a46541db66ae6b4e1af628b7c24c42d3be418f\"}}}", which is really helpful for experimenting and verifying things. [Read More]

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