elm-package-prefixer

Basic usage:

npm i -g elm-package-prefixer

elm-package-prefixer --package-name ianmackenzie/elm-units --prefix Units

All arguments:

  --package-name, -n   [required] The name of the package to prefix.
  --tag, -t            [optional] The version tag to pull from.
  --author, -a         [optional] The author of the generated package.
  --prefix, -p         [required] The prefix to use when generating.
  --out-dir, -d        [optional] The directory to save the generated package.

  --help                          Show this message!
  --help [argument]               Show more detailed info about a particular
                                  argument.

The Problem

This package is a band-aid solution to a problem that arises when one package depends on another, but both packages expose a module (or many) with the same name.

The issue most recently came to light when trying to update the elm-visualization package to use elm-geometry version 3. The core problem is that elm-geometry now uses elm-units throughout its API, but both elm-visualization and elm-units include an exposed Force module (for force-directed layouts and force the physical quantity respectively).

Since elm-geometry uses elm-units types throughout its API, basically any code that depends on/uses elm-geometry directly also has to depend on/use elm-unitsdirectly. However, if elm-visualization depends on elm-units directly, then within the elm-visualization source code import Force is ambiguous - does it refer to the elm-units module or the elm-visualization module?

The Solution

The temporary solution we provide here is to quickly create a prefixed version of an already-published package so that it can be published and depended on where needed. For example, we could wrap the Force module found in elm-units to get something like:

module Units.Force exposing
    ( Force
    , Newtons
    , newtons
    , inNewtons
    , ...
    )

import Force

type alias Force =
    Force.Force

type alias Newtons =
    Force.Newtons

newtons : Float -> Force
newtons =
    Force.newtons

inNewtons : Force -> Float
inNewtons =
    Force.inNewtons

Now, elm-visualization can depend on this package and not worry about the ambiguous Force module name.

Development

• Clone this repository
• run npm install
• run npm run build:dev
• run chmod +x index.js
• run ./index.js --help