eslint-plugin-isaacscript

eslint-plugin-isaacscript is a collection of miscellaneous ESLint rules that can help make your JavaScript/TypeScript code more safe or more strict.

This plugin is named after (and used in) the IsaacScript framework. But you don't have to know anything about IsaacScript to use it - you can use these rules with any JavaScript/TypeScript project.

Alternatively, if you want to get off the ground and running with ESLint + TypeScript in a new project, then you should check out the isaacscript-lint meta-package.

This project is written in TypeScript.

Install / Usage

• npm install --save-dev eslint eslint-plugin-isaacscript
• Add "plugin:isaacscript/recommended" to the extends section of your .eslintrc.js file. (This will automatically add the plugin and add all of the recommended rules.)
  • Alternatively, if you want to only enable some specific rules, then add "isaacscript" to the plugins section of your .eslintrc.js file, and then add the specific rules that you want in the rules section.

Configs

• recommended - Enables just the recommended rules.
• all - Enables all the rules. You would probably never want to use this config, unless you wanted to enable every rule except for one or two specific rules (since specifying a blacklist would be less verbose than specifying a whitelist, in this case).

Rules

Each rule has emojis denoting:

• ✅ - if it belongs to the recommended configuration
• 🔧 - if some problems reported by the rule are automatically fixable by the --fix command line option
• 💭 - if it requires type information

Automatic Fixing

You probably already use Prettier, which is helpful to automatically format files. You probably even have your IDE set up to run Prettier every time your save a file. This kind of thing saves you a tremendous amount of time - you can type out a bunch of code completely unformatted, and then press Ctrl + s at the end to automatically fix everything. (Alternatively, you could press Ctrl + shift + f to format the file without saving it, but it's simpler to just use one hotkey for everything.)

In a similar way to Prettier, this ESLint plugin contains several rules that are designed to automatically apply whenever you save the file (like the format-jsdoc-comments rule). These rules are "fixers", which are applied when ESLint is executed with the "--fix" flag. So, in the same way that you configure Prettier to run on save, you should also configure eslint --fix to run on save.

For example, if you use VSCode, and you have the Prettier and the ESLint extensions installed, you can add the following to your repository's .vscode/settings.json file:

{
  // Automatically run the formatter when certain files are saved.
  "[javascript]": {
    "editor.codeActionsOnSave": ["source.fixAll.eslint"],
    "editor.defaultFormatter": "esbenp.prettier-vscode",
    "editor.formatOnSave": true,
    "editor.tabSize": 2
  },
  "[typescript]": {
    "editor.codeActionsOnSave": ["source.fixAll.eslint"],
    "editor.defaultFormatter": "esbenp.prettier-vscode",
    "editor.formatOnSave": true,
    "editor.tabSize": 2
  }
}

Comment Formatting

For a discussion around comments and the motivations for some of the comment rules in the plugin, see this page.

Contributing

Thanks for helping out with this open-source project!

If you are adding a new rule, start by using the create-rule.sh script to automate a few things:

./create-rule.sh foo "This is a description of the foo rule."
git status # Show what the script did

Additionally, You can contact me on Discord if you are doing a PR and have questions.