stdlint

A non-opinionated development standard linter that helps you keep your repositories clean and consistent!

Table of Contents

• Rationale
• What is stdlint
• Installation
  • Installing per project
  • Installing globally
• Usage
  • Available options
  • Running against a local directory
• Configuring stdlint
• Using Rule Sets
• Writing a rule
• Future work
• Contribution

Rationale

When we work with multiple projects, in a team of developers, we often have to follow some agreed conventions to make sure all our repositories are consistent. Consistency matters a lot especially because if makes it easier to maintain the repositories and enables faster new developer onboarding. However, the conventions we follow as a team of developers can be different depending on the team and developer community.

A few examples for such conventions are,

• package.json should contain the engines field with a valid value
• some_npm_package package should not be used in the repositories, because we want to use another_npm_package package instead.
• Github repository should have branch protection enabled on the default branch.
• PULL_REQUEST_TEMPLATE and CODEOWNERS files should exist in all repositories

Conventions like these can be specific and ad-hoc. It is often very difficult to force each project to follow those rules because checking each project for these conventions can be a time-consuming and a manual task.

What is stdlint

stdlint is a CLI tool which can run a set of rules against a repository and report if the repository configuration and the repository content follows the rules. You can think of it as an "A linter for development conventions".

Installation

Installing per project

To install stdlint in one of your projects, go to the project you need to install stdlint and run the following command:

npm i stdlint --save-dev

After installing stdlint in your project, you can add an npm script to run stdlint in your package.json.

"scripts": {
    "stdlint": "stdlint --path ."
}

You can then run stdlint using your npm script.

npm run stdlint

Installing globally

Although we don't recommend installing stdlint globally, you can do so as follows:

npm i -g stdlint

Once you install stdlint globally, you can use stdlint CLI command from any directory.

Usage

stdlint needs to access github repositories on behalf of you in order to lint its configurations. Therefore, you need to provide stdlint a Github personal access token which grants stdlint API read access to the repositories.

You can pass the personal access token to stdlint by setting it as GITHUB_AUTH_TOKEN environment variable in the same shell stdlint is run.

Available options

$ stdlint --help

Usage: stdlint [options]

Options:
  -p, --path <path>      local path of the project git repository
  -u, --url <url>        github repository URL
  -o, --output <output>  output format for the result. one of json, xml, pretty (default: "pretty")
  -l, --level <level>    maximum error tolerance level (default: 1)
  -h, --help             display help for command

Option	Description
-p or --path	Local path of the project git repository. Can be an absolute path or a relative path
-u or --url	Github repository URL
-l or --level	Maximum tolerance level of errors. Valid values are -1, 0, 1, 2 where the number increases the tolerance level. Set it to -1 to exit with exitCode 1 on all types of issues. e.g: If set to 0, stdlint will exit with exitCode 1 if at least one issue with WARN severity is found.
-h or --help	Display help and usage of the command

Running against a local directory

To run stdlint against a local directory, it is recommended to install stdlint per project and use it with npm scripts. Please refer to the installation instructions.

If you plan to run stdlint with a git CLI hook or a CI stage, you can do so by running stdlint as follows.

stdlint --path <absolute_or_relative_path_to_repository>

e.g, To run stdlint on the current working directory, run stdlint --path .

Configuring stdlint

You can customise the behaviour of the rules or enable/disable them by using a .stdlintrc file at the root of your project.

e.g, You can disable a rule (for example myAwesomeRule), but adding it to the .stdlintrc file as follows:

{
    "rules": {
        "myAwesomeRule": false
    }
}

Some rules can be re-configured too. This is often useful to tweak the rule to fit your needs. If the rule supports customisation, you can pass the rule configuration using .stdlintrc as follows:

{
    "rules": {
        "conventionalCommits": {
            "noOfCommitsToCheck": 5
        }
    }
}

To see if a particular rule supports any configurations, please refer to the documentation of the rule set.

Using Rule Sets

stdlint does not ship with a built-in rule set. You can instruct stdlint to use a rule set by installing it as an npm module and reference the rule set in .stdlintrc as the follows.

Following example shows how to use stdlint-config-bibliocircle rule set with stdlint. You can find the repository for stdlint-config-bibliocircle here.

e.g,

• Install stdlint-config-bibliocircle module in your project
• Update the .stdlintrc as follows.

{
 "extends": [
   "stdlint-config-bibliocircle"
 ],
}

You can extend with more than one rule set by providing them in the "extends" array.

Writing a rule

An example rule is as follows.

module.exports = {
  myAwesomeRule: ({ consts }) => ({
    severity: consts.RULE_SEVERITY.ERROR,
    category: 'Some Rule Category', // stdlint output will be grouped by the 'category' value. This is optional
    checkFunction: async ({ 
        gitClient, // git client
        repoConfig, // github project configuration object
        defaultBranchProtectionConfig, // github branch protection configuration for the default branch
        ruleConfig // custom configuration for the rule passed via `.stdlintrc`
    }) => {
      // Do your checks here, and return an object in the following format:
      return {
        score: 80, // a number between 0-100
        passed: true, // boolean
        message: "Project passed myAwesomeRule with flying colours" // information to show in the stdlint output
      };
    },
  }),
};

Future work

• stdlint only supports Github repositories at the moment. And we'll definitely work towards supporting GitLab and Bitbucket. If you would like stdlint to work with any other git service, please let us know by raising an issue.
• You will need to have git command in the shell where stdlint is run, because stdlint relies on the git command. We are working on making stdlint free of git CLI dependency.

Contribution

I would love to hear your feedback and suggestions. Please do not hesitate to raise an issue to request a feature or report a bug. And if you are interested in contributing, PRs are always welcome! 🎉.