@rxlint/eslint-plugin

This package is a fork of the package cartant/eslint-plugin-rxjs with trimmed and updated dependencies to work with both eslint 8 and 9. Angular-specific rules are in @rxlint/eslint-plugin-angular.

Some rules are opinionated and not included in the recommended configuration. Developers can enable them as needed. Most rules require the TypeScript parser for ESLint but there is a config provided to disable those.

Installation

Install the required packages:

npm install --save-dev eslint typescript @typescript-eslint/parser @rxlint/eslint-plugin
# or
yarn add --dev eslint typescript @typescript-eslint/parser @rxlint/eslint-plugin

Configuration

This plugin works with ESLint v8 (eslintrc) and v9 (eslint.config.js) configuration formats.

ESLint v8 Configuration

Add @rxlint/recommended to your extends array:

.eslintrc.js

module.exports = {
  files: ["**/*.ts"],
  extends: [
    "eslint:recommended",
    "plugin:@typescript-eslint/recommended-type-checked",
    "plugin:@typescript-eslint/stylistic-type-checked",
    "plugin:@rxlint/recommended",
  ],
  parser: "@typescript-eslint/parser",
  parserOptions: {
    ecmaVersion: "latest",
    project: true,
    sourceType: "module",
  },
  rules: {
    "@rxlint/no-async-subscribe": "error",
    "@rxlint/no-ignored-observable": "error",
    "@rxlint/no-ignored-subscription": "error",
    "@rxlint/no-nested-subscribe": "error",
    "@rxlint/no-unbound-methods": "error",
    "@rxlint/throw-error": "error",
  },
};

ESLint v9 Configuration

Import the plugin and add it to the extends array:

eslint.config.js

const rxjs = require("@rxlint/eslint-plugin");

module.exports = [
  {
    files: ["**/*.ts"],
    extends: [
      eslint.configs.recommended,
      tseslint.configs.recommendedTypeChecked,
      tseslint.configs.stylisticTypeChecked,
      rxjs.configs.recommendedTypeChecked,
    ],
  },
];

Disable Type-Aware Linting

Use the disable-type-checked config to turn off type-aware linting for specific file subsets.

ESLint v8

Add @rxlint/disable-type-checked-classic to your extends array:

.eslintrc.js

module.exports = {
  files: ['**/*.{config,test,spec}.{js,ts}'],
  extends: [
    "plugin:@typescript-eslint/disable-type-checked",
    "plugin:@rxlint/disable-type-checked",
  ],
};

ESLint v9

Import the plugin and add rxjs.config.disableTypeChecked to the extends array:

eslint.config.js

module.exports = {
  files: ['**/*.{config,test,spec}.{js,ts}'],
  extends: [
    tseslint.configs.disableTypeChecked,
    rxjs.config.disableTypeChecked,
  ],
};

Rules

The package includes the following rules.

Rules marked with ✅ are recommended and rules marked with 🔧 have fixers.

| Rule | Description | | | | --- | --- | --- | --- | | ban-observables | Forbids the use of banned observables. | | | | ban-operators | Forbids the use of banned operators. | | | | finnish | Enforces the use of Finnish notation. | | | | just | Enforces the use of a just alias for of. | | 🔧 | | no-async-subscribe | Forbids passing async functions to subscribe. | ✅ | | | no-compat | Forbids importation from locations that depend upon rxjs-compat. | | | | no-connectable | Forbids operators that return connectable observables. | | | | no-create | Forbids the calling of Observable.create. | ✅ | | | no-cyclic-action | Forbids effects and epics that re-emit filtered actions. | | | | no-explicit-generics | Forbids explicit generic type arguments. | | | | no-exposed-subjects | Forbids exposed (i.e. non-private) subjects. | | | | no-finnish | Forbids the use of Finnish notation. | | | | no-ignored-error | Forbids the calling of subscribe without specifying an error handler. | | | | no-ignored-notifier | Forbids observables not composed from the repeatWhen or retryWhen notifier. | ✅ | | | no-ignored-observable | Forbids the ignoring of observables returned by functions. | | | | no-ignored-replay-buffer | Forbids using ReplaySubject, publishReplay or shareReplay without specifying the buffer size. | ✅ | | | no-ignored-subscribe | Forbids the calling of subscribe without specifying arguments. | | | | no-ignored-subscription | Forbids ignoring the subscription returned by subscribe. | | | | no-ignored-takewhile-value | Forbids ignoring the value within takeWhile. | ✅ | | | no-implicit-any-catch | Like the no-implicit-any-catch rule in @typescript-eslint/eslint-plugin, but for the catchError operator instead of catch clauses. | ✅ | 🔧 | | no-index | Forbids the importation from index modules - for the reason, see this issue. | ✅ | | | no-internal | Forbids the importation of internals. | ✅ | 🔧 | | no-nested-subscribe | Forbids the calling of subscribe within a subscribe callback. | ✅ | | | no-redundant-notify | Forbids redundant notifications from completed or errored observables. | ✅ | | | no-sharereplay | Forbids using the shareReplay operator. | ✅ | | | no-subclass | Forbids subclassing RxJS classes. | | | | no-subject-unsubscribe | Forbids calling the unsubscribe method of a subject instance. | ✅ | | | no-subject-value | Forbids accessing the value property of a BehaviorSubject instance. | | | | no-subscribe-handlers | Forbids the passing of handlers to subscribe. | | | | no-topromise | Forbids the use of the toPromise method. | | | | no-unbound-methods | Forbids the passing of unbound methods. | ✅ | | | no-unsafe-catch | Forbids unsafe catchError usage in effects and epics. | | | | no-unsafe-first | Forbids unsafe first/take usage in effects and epics. | | | | no-unsafe-subject-next | Forbids unsafe optional next calls. | ✅ | | | no-unsafe-switchmap | Forbids unsafe switchMap usage in effects and epics. | | | | no-unsafe-takeuntil | Forbids the application of operators after takeUntil. | ✅ | | | prefer-observer | Forbids the passing separate handlers to subscribe and tap. | | 🔧 | | suffix-subjects | Enforces the use of a suffix in subject identifiers. | | | | throw-error | Enforces the passing of Error values to error notifications. | | |