tslint-jest

1.0.5 verified Fri May 01 auth: no javascript deprecated

tslint-jest is a TSLint plugin providing lint rules for Jest test files. Version 1.0.5 is the latest stable release; the package is no longer actively maintained as TSLint is deprecated in favor of ESLint. It offers rules such as no-alias-methods and expect-expect. Unlike alternatives (eslint-plugin-jest), this plugin is specific to TSLint and is only useful for projects still using TSLint.

Common errors

error Cannot find module 'tslint-jest' ↓

cause The package is not installed or not in node_modules.

fix

Run npm install --save-dev tslint-jest.

error Invalid rules configuration: unknown rule 'no-alias-methods' ↓

cause tslint-jest extension not added to tslint.json.

fix

Ensure "extends": ["tslint-jest"] is present in tslint.json.

error TypeError: Cannot read property 'apply' of undefined (TSLint error) ↓

cause Incompatible TSLint version or plugin not loaded.

fix

Stick to TSLint 5.x and tslint-jest 1.0.x.

Warnings

deprecated TSLint is deprecated in favor of ESLint; tslint-jest is no longer maintained. ↓

fix Use eslint-plugin-jest with ESLint instead.

gotcha Rules are only available via tslint.json; you cannot import them programmatically in code. ↓

fix Always define rules in tslint.json configuration file.

gotcha expect-expect rule may flag tests with no explicit assertions inside `it` or `test` blocks even if they contain async calls that throw. ↓

fix Use the `assertFunctionNames` option to whitelist custom assertion functions.

Install

npm install tslint-jest

yarn add tslint-jest

pnpm add tslint-jest

Imports

no-alias-methods

wrong

import { no-alias-methods } from 'tslint-jest'

correct

{
  "extends": ["tslint-jest"],
  "rules": {
    "no-alias-methods": true
  }
}

Rules are specified in tslint.json configuration, not imported in code.

expect-expect

wrong

const { expect-expect } = require('tslint-jest')

correct

{
  "extends": ["tslint-jest"],
  "rules": {
    "expect-expect": true
  }
}

Configure rules in tslint.json, not via require/import.

tslint-jest configuration
wrong
```
require('tslint-jest')
```
correct
```
{
  "extends": ["tslint-jest"]
}
```
The package is a TSLint ruleset; it is used by adding to 'extends' array in tslint.json, not by requiring in code.

Quickstart

Install tslint-jest, configure rules in tslint.json, and lint Jest test files.

// Step 1: Install
yarn add --dev tslint-jest

// Step 2: Configure tslint.json
{
  "extends": ["tslint-jest"],
  "rules": {
    "no-alias-methods": true,
    "expect-expect": [true, { "assertFunctionNames": ["expect", "assert"] }]
  }
}

// Step 3: Run tslint on a test file
npx tslint --project tsconfig.json 'src/**/*.test.ts'