eslint-plugin-es-roikoren

A re-implementation of eslint-plugin-es in TypeScript.

Disclaimer

First off, I would like to deeply thank @mistycatea and everyone else involved in the original eslint-plugin-es. None of this would have been possible without them, and all credit should go to them.

This package is an attempt to migrate eslint-plugin-es to be written in TypeScript, and to use the great @typescript-eslint repository for plugin development.

Below is taken verbatim from eslint-plugin-es, and will be updated as needed.

🏁 Goal

Espree, the default parser of ESLint, has supported ecmaVersion option. However, the error messages of new syntax are not readable (e.g., "unexpected token" or something like).

When we use this plugin along with the latest ecmaVersion option value, it tells us the readable error message for the new syntax, such as "ES2020 BigInt is forbidden." Plus, this plugin lets us disable each syntactic feature individually.

💿 Installation

Use npm or a compatible tool.

npm install --save-dev eslint eslint-plugin-es-roikoren

yarn add -D eslint eslint-plugin-es-roikoren

IMPORTANT

If you installed eslint globally, you should install this plugin in the same way.

Requirements

• Node.js 12.22.0 or newer.
• ESLint 7.0.0 or newer.

📖 Usage

Configure your .eslintrc.* file.

For example, to enable only Rest/Spread Properties in ES2018, as similar to legacy experimentalObjectRestSpread option:

{
  "plugins": ["es-roikoren"],
  "parserOptions": {
    "ecmaVersion": 2018
  },
  "rules": {
    "es-roikoren/no-async-iteration": "error",
    "es-roikoren/no-malformed-template-literals": "error",
    "es-roikoren/no-regexp-lookbehind-assertions": "error",
    "es-roikoren/no-regexp-named-capture-groups": "error",
    "es-roikoren/no-regexp-s-flag": "error",
    "es-roikoren/no-regexp-unicode-property-escapes": "error"
  }
}

Presets

This plugin provides the following configs.

Config ID	Description
plugin:es-roikoren/restrict-to-es2020	disallow new stuff that ES2020 doesn't include.
plugin:es-roikoren/restrict-to-es2019	disallow new stuff that ES2019 doesn't include.
plugin:es-roikoren/restrict-to-es2018	disallow new stuff that ES2018 doesn't include.
plugin:es-roikoren/restrict-to-es2017	disallow new stuff that ES2017 doesn't include.
plugin:es-roikoren/restrict-to-es2016	disallow new stuff that ES2016 doesn't include.
plugin:es-roikoren/restrict-to-es2015	disallow new stuff that ES2015 doesn't include.
plugin:es-roikoren/restrict-to-es5	disallow new stuff that ES5 doesn't include.
plugin:es-roikoren/restrict-to-es3	disallow new stuff that ES3 doesn't include.
plugin:es-roikoren/no-new-in-es2021	disallow the new stuff in ES2021.
plugin:es-roikoren/no-new-in-es2020	disallow the new stuff in ES2020.
plugin:es-roikoren/no-new-in-es2019	disallow the new stuff in ES2019.
plugin:es-roikoren/no-new-in-es2018	disallow the new stuff in ES2018.
plugin:es-roikoren/no-new-in-es2017	disallow the new stuff in ES2017.
plugin:es-roikoren/no-new-in-es2016	disallow the new stuff in ES2016.
plugin:es-roikoren/no-new-in-es2015	disallow the new stuff in ES2015.
plugin:es-roikoren/no-new-in-es5	disallow the new stuff in ES5.
plugin:es-roikoren/no-new-in-esnext	disallow the new stuff to be planned for the next yearly ECMAScript snapshot. ⚠️ This config will be changed in the minor versions of this plugin.
plugin:es-roikoren/typescript	turn off rules for stuff that TypeScript transpiles correctly, regardless of target ES version.

For example:

{
  "parserOptions": {
    "ecmaVersion": 2021
  },
  "extends": [
    "eslint:recommended",
    "plugin:es-roikoren/restrict-to-es2018"
  ],
  "rules": {
    "es-roikoren/no-rest-spread-properties": "off"
  }
}

The aggressive mode

This plugin never reports prototype methods by default. Because it's hard to know the type of objects, it will cause false positives.

If you configured the aggressive mode, this plugin reports prototype methods even if the rules couldn't know the type of objects. For example:

settings.es.aggressive = true means the aggressive mode.

{
  "plugins": ["es-roikoren"],
  "rules": {
    "es-roikoren/no-string-prototype-codepointat": "error"
  },

  "settings": {
    "es": { "aggressive": true }
  }
}

If using this plugin and TypeScript, this plugin reports prototype methods by default because we can easily know types. For example:

{
  "plugins": ["es-roikoren"],
  "parser": "@typescript-eslint/parser",
  "parserOptions": {
    "project": "tsconfig.json"
  },
  "rules": {
    "es-roikoren/no-string-prototype-codepointat": "error"
  }
}

If you configured the aggressive mode, this plugin reports prototype methods on any types as well.

{
  "plugins": ["es-roikoren"],
  "parser": "@typescript-eslint/parser",
  "parserOptions": {
    "project": "tsconfig.json"
  },
  "rules": {
    "es-roikoren/no-string-prototype-codepointat": "error"
  },
  "settings": {
    "es": { "aggressive": true }
  }
}