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2.2.6 • Public • Published

elm-review CLI

Run elm-review from Node.js.

elm-review reporter output


# Save it to your package.json, if you use npm in your project. 
# This is the recommended way. 
npm install elm-review --save-dev
# Install globally. This is not recommended. 
npm install -g elm-review


elm-review --help       # Print the help 
elm-review              # Review your project 
elm-review init         # Create an empty review configuration 
elm-review new-package  # Create a new project containing elm-review rules 
                        # aimed at being published on the Elm package registry 
elm-review new-rule     # Create an empty new rule to get started. 
                        # Very helpful for projects created with new-package 


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

elm-review init
elm-review init --help # for more information and the available flags 

This will create a review/ directory containing an elm.json and a ReviewConfig.elm file, which you should commit into your project. Here is what it may look like:

module ReviewConfig exposing (config)
import Review.Rule exposing Rule
import NoDebug
import NoUnused.Variables
config : List Rule
config =
    [ NoDebug.rule
    , NoUnused.Variables.rule

elm-review does not come with any built-in rules. You can read why here. You can find rules in the Elm package registry by using elm-search and searching for Review.Rule.Rule, and use them by going to your review/ directory and running elm install in your terminal.

cd review/ # Go inside your review configuration directory 
elm install authorName/packageName

Run a review

Once you're done configuring, run elm-review to analyze your project.

You can also run elm-review --fix. The CLI will present you fixes for the errors that offer an automatic fix, which you can then accept or not. When there are no more fixable errors left, elm-review will report the remaining errors as if it was called without --fix. Fixed errors will be reformatted using elm-format.

Run elm-review --help for more information on the available flags.

elm-review # Analyze your project 
elm-review --fix # Analyze your project and potentially proposes automatic fixes 
elm-review --help # for more information and the available flags 

Which parts of the project will be analyzed?

elm-review targets a project, and therefore requires an elm.json. By default, it will review all the Elm files of the project and of the tests.

  • For packages: all the Elm files in src/ and tests/
  • For applications: all the Elm files in tests/ and in the project's elm.json's source-directories

If you wish to, you can list the directories you wish to have reviewed, so as to review additional directories or to remove ignore some of directories, by adding them as arguments to the command line.

# Review `src/` if project is a package, or the "source-directories" otherwise, along with `tests/` 
# Review only the Elm files in the `src/Dashboard/` 
elm-review src/Dashboard/
# Review all the Elm files in the src/, tests/ and review/ directories 
elm-review src/ tests/ review/
# Review a specific file 
elm-review src/Dashboard.elm

The recommended way to use elm-review is without arguments. It is best not to "remove" directories from the project, because some rules expect to have access to all the files in order to make the best analysis. If some data is missing, they may make incorrect reports. If you wish to ignore some files, it is best to handle that in the implementation and/or configuration of your rules.

If you add files that are not part of the project, you may run into different problems, such as conflicting module names (two Main.elm files), relying on different dependencies, etc. It is best to run elm-review once for each project, and depending on your needs, with different configurations (using the --config flag).

Exit status

If any rule from your configuration reports an error in one of the analyzed files, the process will exit with status 1. Otherwise, it will exit with status 0.

If the process fails for any other reason (crash, misconfiguration, ...), it will exit with status 1.

Why is there a need for a review/ directory?

When the CLI looks at your configuration, it is in practice compiling an application using the configuration in your project, then running that application to analyze your project.

The CLI need at least two pieces of information from your configuration:

  • An elm.json file to know the external packages your configuration depends upon (like the ones that contain the rules you enabled), and the Elm version of your project
  • A ReviewConfig.elm file that sets the rules to enforce for your project

Your custom rules, unless you want to share them in the Elm package registry, should be in the review/ directory too, so as not to pollute your project's dependencies. If they are in here, we need to include these custom rules and their dependencies in the application files.

Tooling integration

If you are interested in using elm-review inside a different environment than a terminal (like editors, CI, other Elm tools, ...), check out the documentation for tooling integration.


npm i elm-review

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