Elm coder generator

Builds JSON decoders and encoders for your Elm types.

Demo using the kakoune editor piping to the CLI.

Coverage

Module	decls	let decls	lambdas	branches
total	96/151 (64%)	117/168 (70%)	10/13 (77%)	190/436 (44%)

Installation

npm i -g elm-coder-generator

CLI

Generate decoders for Example.elm (available in this repo):

It grabs and generates code only for type definitions inside these annotations.

elm-coder-generator Example.elm

Or pipe to elm-coder-generator:

echo '-- [generator-start]\n type X = Int\n-- [generator-end]' | elm-coder-generator 

output

-- [generator-start]
 type X = Int
 
-- [elm-generator-start] -- DO NOT MODIFY or remove this line
decodeX =
   Decode.int
 
encodeX a =
   Encode.int a 
-- [generator-end]

API

const generate = require('elm-coder-generator')

generate('-- [generator-start]\n type X = Int\n -- [generator-end]').then(x => console.log(x))

// -> decodeX =
// ->    Decode.int
// -> 
// -> encodeX a =
// ->    Encode.int a

Development

Clone the repo and build Cli.elm:

$ git clone https://github.com/franzskuffka/elm-coder-generator
$ cd elm-coder-generator
$ elm make src/Cli.elm --output elm-stuff/Cli.js --optimize

Roadmap

• support for different data formats
• IDE plugins
• codec support for encoder / decoder pairs https://package.elm-lang.org/packages/miniBill/elm-codec/latest/
• compile plugin / pragma?

Acknowledgements

Special thanks to Dániel Kodaj @dkodaj for building the meat of the coder generator.

Of course, thanks to @evancz and @stoeffel.