node-elm-lint

Run elm-lint from Node.js.

Installation

npm install -g elm-lint

Usage

elm-lint --help  # Print the help
elm-lint init    # Creates a `LintConfig.elm` file in which you can declare how you want to configure elm-lint
elm-lint         # Lint your project

Configuration

To run elm-lint for the first time, you need to run

elm-lint init

This will create a LintConfig.elm file at the root of your project, which looks like the following:

module LintConfig exposing (config)

import Lint.Types exposing (LintRule, Severity(..))
import Lint.Rules.DefaultPatternPosition
import Lint.Rules.NoDebug
import Lint.Rules.NoUnusedVariables


config : List ( Severity, LintRule )
config =
    [ ( Critical, Lint.Rules.DefaultPatternPosition.rule { position = Lint.Rules.DefaultPatternPosition.Last } )
    , ( Warning, Lint.Rules.NoDebug.rule )
    , ( Critical, Lint.Rules.NoUnusedVariables.rule )
    ]

The configuration consists of a list of linting rules. Rules are Import the rules you wish to use and pair them with a severity level (Critical / Warning). A reported Critical error will make elm-lint return a failure exit code, while a Warning error will not. You can see the full list of rules here. Do note that some rules will need additional configuration, but don't worry, if you misconfigure elm-lint, the Elm compiler will tell you.

Once you're done configuring, run elm-lint and you should be good to go.

FAQ

• I get the error (Critical) Parsing error: expected end of input for some of my files, what is happening?

This means that your file could not be parsed. You should try and copy-paste that file's source code into the elm-ast online demo to see if you can reproduce the error. If you are able to, then try to make a minimal reproducible example and open an issue on elm-ast.

In most cases, this is due to comments made using -- (e.g. -- a comment) that are not well handled by the parser. elm-lint tries to remove them before parsing, but does a bad job at it at the moment (help wanted).

• Thanks for pointing out the error, but I would like to know where in my code the error is.

At the moment, elm-ast is missing positional information on the generated AST, that elm-lint uses. You can follow this issue if you want to know more or to contribute.

• I have an idea for a rule, how can I get it integrated into elm-lint?

Please open an issue on elm-lint so we can talk about it. Try to make your proposal look like this.

elm-lint would like to be able to provide support for a plugin system so that you can work on it without my approval. Maybe that already works, but if it doesn't, please open an issue about that.

• The code looks bad and can be improved upon, also the documentation is lacking.

You're absolutely right. Please open an issue if you have suggestions or open a pull request!