eslint-plugin-rxjs-x

This ESLint plugin is intended to prevent issues with RxJS.

Most of these rules require TypeScript typed linting and are indicated as such below.

Migration Guide from eslint-plugin-rxjs

This project started as a fork of eslint-plugin-rxjs but has since introduced new features which involve breaking changes.

1. Migrate your config from the old .eslintrc format to eslint.config.mjs (or similar), and uninstall eslint-plugin-rxjs.

   • See ESLint's guide here: [https://eslint.org/docs/latest/use/configure/migration-guide].
   • If you need to continue using the deprecated format, use the original eslint-plugin-rxjs or a different fork.

2. Install eslint-plugin-rxjs-x, and import it into your config.

   + import rxjsX from 'eslint-plugin-rxjs-x';

3. If you previously used the plugin:rxjs/recommended shared config, add rxjsX.configs.recommended to your configs block:

   configs: {
   +   rxjsX.configs.recommended,
   },

   • Note: eslint-plugin-rxjs-x provides a strict shared config, so consider using rxjsX.configs.strict instead.

4. If you previously did not use a shared config, add the plugin to your plugins block with the new namespace:

   plugins: {
   +   'rxjs-x': rxjsX,
   },

   • Note: this is unnecessary if you are using a shared config.

5. In your rules block, replace the namespace rxjs with rxjs-x:

   -   'rxjs/no-subject-value': 'error',
   +   'rxjs-x/no-subject-value': 'error',

6. If you previously used rxjs/no-ignored-observable, replace it with rxjs-x/no-floating-observables.

   -   'rxjs/no-ignored-observable': 'error',
   +   'rxjs-x/no-floating-observables': 'error',

[!TIP] A complete description of all changes are documented in the CHANGELOG file.

Installation Guide

See typescript-eslint's Getting Started for a full ESLint setup guide.

1. Enable typed linting.
   • See Linting with Type Information for more information.
2. Start with the recommended shared config in your eslint.config.mjs.

// @ts-check
import { defineConfig } from 'eslint/config';
import tseslint from 'typescript-eslint';
import rxjsX from 'eslint-plugin-rxjs-x';

export default defineConfig({
    extends: [
        ...tseslint.configs.recommended,
        rxjsX.configs.recommended,
    ],
    languageOptions: {
        parserOptions: {
            projectService: true,
        },
    },
});

Configs

| | Name | | :- | :------------ | | ✅ | recommended | | 🔒 | strict |

Rules

The package includes the following rules.

💼 Configurations enabled in.
✅ Set in the recommended configuration.
🔒 Set in the strict configuration.
🔧 Automatically fixable by the --fix CLI option.
💡 Manually fixable by editor suggestions.
💭 Requires type information.
❌ Deprecated.

| Name                            | Description | 💼 | 🔧 | 💡 | 💭 | ❌ | | :------------------------------------------------------------------------------- | :-------------------------------------------------------------------------------------------------------- | :--- | :- | :- | :- | :- | | ban-observables | Disallow banned observable creators. | | | | | | | ban-operators | Disallow banned operators. | | | | 💭 | | | finnish | Enforce Finnish notation. | | | | 💭 | | | just | Require the use of just instead of of. | | 🔧 | | | | | macro | Require the use of the RxJS Tools Babel macro. | | 🔧 | | | ❌ | | no-async-subscribe | Disallow passing async functions to subscribe. | ✅ 🔒 | | | 💭 | | | no-compat | Disallow the rxjs-compat package. | | | | | ❌ | | no-connectable | Disallow operators that return connectable observables. | | | | 💭 | | | no-create | Disallow the static Observable.create function. | ✅ 🔒 | | | 💭 | | | no-cyclic-action | Disallow cyclic actions in effects and epics. | | | | 💭 | | | no-explicit-generics | Disallow unnecessary explicit generic type arguments. | | | | | | | no-exposed-subjects | Disallow public and protected subjects. | 🔒 | | | 💭 | | | no-finnish | Disallow Finnish notation. | | | | 💭 | | | no-floating-observables | Require Observables to be handled appropriately. | 🔒 | | | 💭 | | | no-ignored-default-value | Disallow using firstValueFrom, lastValueFrom, first, and last without specifying a default value. | 🔒 | | | 💭 | | | no-ignored-error | Disallow calling subscribe without specifying an error handler. | 🔒 | | | 💭 | | | no-ignored-notifier | Disallow observables not composed from the repeatWhen or retryWhen notifier. | ✅ 🔒 | | | 💭 | | | no-ignored-replay-buffer | Disallow using ReplaySubject, publishReplay or shareReplay without specifying the buffer size. | ✅ 🔒 | | | | | | no-ignored-subscribe | Disallow calling subscribe without specifying arguments. | | | | 💭 | | | no-ignored-subscription | Disallow ignoring the subscription returned by subscribe. | | | | 💭 | | | no-ignored-takewhile-value | Disallow ignoring the value within takeWhile. | ✅ 🔒 | | | | | | no-implicit-any-catch | Disallow implicit any error parameters in catchError operators. | ✅ 🔒 | 🔧 | 💡 | 💭 | | | no-index | Disallow importing index modules. | ✅ 🔒 | | | | | | no-internal | Disallow importing internal modules. | ✅ 🔒 | 🔧 | 💡 | | | | no-misused-observables | Disallow Observables in places not designed to handle them. | 🔒 | | | 💭 | | | no-nested-subscribe | Disallow calling subscribe within a subscribe callback. | ✅ 🔒 | | | 💭 | | | no-redundant-notify | Disallow sending redundant notifications from completed or errored observables. | ✅ 🔒 | | | 💭 | | | no-sharereplay | Disallow unsafe shareReplay usage. | ✅ 🔒 | | | | | | no-sharereplay-before-takeuntil | Disallow using shareReplay({ refCount: false }) before takeUntil. | 🔒 | | | | | | no-subclass | Disallow subclassing RxJS classes. | 🔒 | | | 💭 | | | no-subject-unsubscribe | Disallow calling the unsubscribe method of subjects. | ✅ 🔒 | | | 💭 | | | no-subject-value | Disallow accessing the value property of a BehaviorSubject instance. | | | | 💭 | | | no-subscribe-handlers | Disallow passing handlers to subscribe. | | | | 💭 | | | no-subscribe-in-pipe | Disallow calling of subscribe within any RxJS operator inside a pipe. | ✅ 🔒 | | | 💭 | | | no-tap | Disallow the tap operator. | | | | | ❌ | | no-topromise | Disallow use of the toPromise method. | ✅ 🔒 | | 💡 | 💭 | | | no-unbound-methods | Disallow passing unbound methods. | ✅ 🔒 | | | 💭 | | | no-unnecessary-collection | Disallow unnecessary usage of collection arguments with single values. | 🔒 | | | | | | no-unsafe-catch | Disallow unsafe catchError usage in effects and epics. | | | | 💭 | | | no-unsafe-first | Disallow unsafe first/take usage in effects and epics. | | | | 💭 | | | no-unsafe-subject-next | Disallow unsafe optional next calls. | ✅ 🔒 | | | 💭 | | | no-unsafe-switchmap | Disallow unsafe switchMap usage in effects and epics. | | | | 💭 | | | no-unsafe-takeuntil | Disallow applying operators after takeUntil. | ✅ 🔒 | | | 💭 | | | prefer-observer | Disallow passing separate handlers to subscribe and tap. | ✅ 🔒 | 🔧 | 💡 | 💭 | | | prefer-root-operators | Disallow importing operators from rxjs/operators. | ✅ 🔒 | 🔧 | 💡 | | | | suffix-subjects | Enforce the use of a suffix in subject identifiers. | | | | 💭 | | | throw-error | Enforce passing only Error values to throwError or Subject.error. | ✅ 🔒 | | | 💭 | |