rxjs-tslint-rules

rxjs-tslint-rules

TSLint is deprecated. All of the rules in this package - with the exception of the RxJS-version-5-only rules - have equivalent ESLint rules in the eslint-plugin-rxjs and eslint-plugin-rxjs-angular packages.

If you've arrived here looking for the TSLint rules that automatically convert RxJS version 5 code to version 6, you can find those rules here: rxjs-tslint.

That said, if you've not already done so, you might want to checkout the rules in this package, too. Using them, you can avoid potential problems and questionable practices.

What is it?

rxjs-tslint-rules is set of TSLint rules to:

• help manage projects that use rxjs/add/... imports;
• enforce or disallow Finnish notation; and
• highlight other potential problems (see the rules for details).

Why might you need it?

When using imports that patch Observable:

import { Observable } from "rxjs/Observable";
import "rxjs/add/observable/of";
import "rxjs/add/operator/map";

TypeScript will see the merged declarations in all modules, making it difficult to find rxjs/add/... imports that are missing from modules in which patched observables and operators are used.

This can cause problems, as whether or not Observable is patched then depends upon the order in which the modules are executed.

The rules in this package can be used to highlight missing - or unused - imports and other potential problems with RxJS.

There are some examples of policies that can be implemented using particular rule combinations in:

• Managing RxJS Imports with TSLint; and
• Understanding Lettable Operators.
• TSLint Rules for Version 6

And Christian Liebel has written about his approach to importing RxJS in his blog post:

• Angular & TypeScript: How to Import RxJS Correctly?

Install

Install the package using NPM:

npm install rxjs-tslint-rules --save-dev

Update your tslint.json file to extend this package:

{
  "extends": [
    "rxjs-tslint-rules"
  ],
  "rules": {
    "rxjs-add": { "severity": "error" },
    "rxjs-no-unused-add": { "severity": "error" }
  }
}

Rules

WARNING: Before configuring any of the following rules, you should ensure that TSLint's no-unused-variable rule is not enabled in your configuration (or in any configuration that you extend). That rule has caused problems in the past - as it leaves the TypeScript program in an unstable state - and has a significant number of still-open issues. Consider using the no-unused-declaration rule from tslint-etc instead.

The package includes the following rules (none of which are enabled by default):

Options

rxjs-add

The rxjs-add rule takes an optional object with the property file. This is the path of the module - relative to the tsconfig.json - that imports the patched observables and operators.