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.	✅ 🔒			💭