Eucalypt is a frontend library for Squint ClojureScript. It replaces Reagent & React with a compatible-ish subset of the Reagent API. It supports form-1 and form-2 Reagent components.

The goal is to build very small frontend artifacts (~10k) using "Reagent" and "ClojureScript" (if you squint hard enough). It's suitable for small pieces of one-off frontend code that do something simple, not large production web apps. The examples from the Reagent homepage have been ported and work with Eucalypt. Eucalypt is itself very small and fits in a single cljs file.

• Try the demo - a single HTML file artifact gzipped to ~14k.
• See the demo source code for examples.
• Tests source code
• Note: Eucalypt was slop-coded with AI and low human oversight so please be careful.

What's with the name? Eucalyptus oil, which is sometimes used in cleaning, looks like a reagent if you squint hard enough.

Use | Bugs | Gotchas | Dev | Tests | Build | Use of AI | Mr Clean

Install with npm:

npm i eucalypt

Use it in your Squint cljs script like this:

(ns my-app
  (:require
    [eucalypt :as r]))

(defonce state (r/atom {}))

(defn component:main [state]
  [:<>
    [:p "Hello world!"]
    [:pre (pr-str @state)]])

(r/render
  [component:main state]
  (js/document.getElementById "app"))

There's also a "create" script you can use to bootstrap a Squint, Vite, and Eucalypt project:

npm create eucalypt myapp
cd myapp
npm install
npm run watch
npm run build # <- builds a dist/index.html

Thanks to @borkdude for this example.

import { render, atom } from "https://esm.sh/eucalypt";
import { deref, swap_BANG_, update_in } from "https://esm.sh/squint-cljs/core.js";

const swap = swap_BANG_;

const state = atom({counter: 0});

function myComponent () {
 return ["<>",
          ["div", "Hello world"],
          ["div", "Counter: ", deref(state).counter],
          ["button", {"on-click": () => {
            console.log('clock')
            swap(state, update_in, ["counter"], (x) => x + 1);           
            }
          }, "inc"]
        ];
}

render([myComponent], document.getElementById("app"))

If you find an example form-1 or form-2 component that works in Reagent but doesn't work with Eucalypt, please create a failing test case in the tests/src folder, and raise a PR.

Eucalypt gotchas:

• Not currently reentrant. State is shared globally.
• The only well-tested API is r/atom and r/render.
• Lots and lots of other weirdness and edge cases for sure.
• Only the :component-will-unmount lifecycle hook is currently wired up. Other Reagent lifecycle keys are not yet implemented yet (but :ref is).
• It's slop code.

Some things to watch out for when using Squint, which I ran into building this:

• Keywords are just strings. No keyword?, name etc.
• No binding.
• No sorted-hashmap.

We are using pnpm for dev. You don't have to but it will probably help.

pnpm i
pnpm watch

pnpm test

pnpm build

Eucalypt is a fork of Mr Clean that has been slop-coded with AI into compiling with Squint.

Slop-coded means this library was built by:

1. Creating failing test cases.
2. Using various LLMs to fix the code until all tests pass.

If you're uncomfortable with this method of development, which involves less human oversight, then you may want to be careful when using this library. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED.

Mr Clean is a Reagent compatible ClojureScript library without dependency on React.js. At the heart of React.js is a very simple idea GUI = function(data). Reagent takes this idea even further hiccup = function(data). The advantage of using Mr Clean over Reagent is that the generated javascript of a hello-world app is half the size of that of reagent.

There is no diffing of virtual DOM. The state of components is flushed to the DOM when data changes.

Ractive atoms and cursors work as expected which are the important parts making components reactive to data changes. form 1, form 2 components are fully supported.

None of the reagent macros are implemented. r/reaction is not a macro but a function that returns an atom holding the result of evaluating a function.

form 3 components are not fully supported because not all lifecycle methods are implemented.