application.md

elm.json for applications

This is a decent baseline for pretty much any applications made with Elm. You will need these dependencies or more.

{
    "type": "application",
    "source-directories": [
        "src"
    ],
    "elm-version": "0.19.1",
    "dependencies": {
        "direct": {
            "elm/browser": "1.0.0",
            "elm/core": "1.0.0",
            "elm/html": "1.0.0",
            "elm/json": "1.0.0"
        },
        "indirect": {
            "elm/time": "1.0.0",
            "elm/url": "1.0.0",
            "elm/virtual-dom": "1.0.0"
        }
    },
    "test-dependencies": {
        "direct": {},
        "indirect": {}
    }
}

"type"

Either "application" or "package". All the other fields are based on this choice!

"source-directories"

A list of directories where Elm code lives. Most projects just use "src" for everything.

"elm-version"

The exact version of Elm this builds with. Should be "0.19.1" for most people!

"dependencies"

All the packages you depend upon. We use exact versions, so your elm.json file doubles as a "lock file" that ensures reliable builds.

You can use modules from any "direct" dependency in your code. Some "direct" dependencies have their own dependencies that folks typically do not care about. These are the "indirect" dependencies. They are listed explicitly so that (1) builds are reproducible and (2) you can easily review the quantity and quality of dependencies.

Note: We plan to eventually have a screen in reactor that helps add, remove, and upgrade packages. It can sometimes be tricky to keep all of the constraints happy, so we think having a UI will help a lot. If you get into trouble in the meantime, adding things back one-by-one often helps, and I hope you do not get into trouble!

"test-dependencies"

All the packages that you use in tests/ with elm-test but not in the application you actually want to ship. This also uses exact versions to make tests more reliable.