Awesome
melange-opam-template
A simple project template using Melange with opam.
If you are looking for a template with esy, check melange-esy-template.
Quick Start
npm run init
# In separate terminals:
npm run watch
npm run serve
React
React support is provided by
reason-react
. The entry
point of the sample React app is src/ReactApp.re
.
Commands
All the build commands are defined in the scripts
field of package.json
. This
is completely optional, and other tools like make
could be used.
You can see all available commands by running npm run
. There are explanations
on each command in the scriptsComments
field of the package.json
file.
Here are a few of the most useful ones:
npm run init
: set up opam local switch and download OCaml, Melange and JavaScript dependenciesnpm run install-opam-npm
: install OCaml, Melange and JavaScript dependenciesnpm run watch
: watch for the filesystem and have Melange rebuild on every changenpm run serve
: serve the application with a local HTTP server
JavaScript output
Since Melange compiles source files into JavaScript files, it can be used for projects on any JavaScript platform - not just the browser.
The template includes two melange.emit
stanza for two separate apps. This
stanza tells Dune to generate JavaScript files using Melange, and specifies in
which folder the JavaScript files should be placed, by leveraging the target
field:
- The React app JavaScript files will be placed in
_build/default/src/output/*
. - The NodeJS app JavaScript files will be placed in
_build/default/src/node/*
.
So for example, src/Hello.ml
(using OCaml syntax) can be run with
node
:
node _build/default/src/node/src/Hello.mjs
Similarly, _build/default/src/output/src/ReactApp.js
can be passed as entry to a bundler
like Webpack:
webpack --mode production --entry ./_build/default/src/output/src/ReactApp.js