Registry / testing / eslint-plugin-redundant-undefined

eslint-plugin-redundant-undefined

library1.0.0jsnpmunverified

An ESLint plugin (v1.0.0, single release so far) that forbids redundant `undefined` in TypeScript optional parameters and properties. It helps enforce cleaner optional types by flagging patterns like `s?: string | undefined` and offering a `followExactOptionalPropertyTypes` option for use with TypeScript's `exactOptionalPropertyTypes` setting. Requires `@typescript-eslint/parser` and ESLint >=8.46.0. Available on npm with MIT license.

testing

npm install eslint-plugin-redundant-undefined

github ↗package ↗

INSTALL

IMPORT

SIG · ESLINT-PLUGIN-REDU

eslint-plugin-redundant-undefined

testingjavascriptv1.0.0

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

redundant-undefined

✓ // In .eslintrc: { "plugins": ["redundant-undefined"], "rules": { "redundant-undefined/redundant-undefined": "error" } }

✗ require('eslint-plugin-redundant-undefined') or import syntax in config is not supported

Plugin is added via plugins array in ESLint config; rules are prefixed with 'redundant-undefined/'

default rule

✓ rules: { "redundant-undefined/redundant-undefined": "error" }

✗ Setting 'redundant-undefined' as a top-level rule like 'redundant-undefined': 'error' (missing slash) or using wrong rule name

Rule name is 'redundant-undefined/redundant-undefined' – the plugin name and rule name are identical but separated by a slash

Minimal ESLint config to enable the plugin and rule, plus an example of incorrect code.

// .eslintrc.json { "parser": "@typescript-eslint/parser", "plugins": ["redundant-undefined"], "rules": { "redundant-undefined/redundant-undefined": "error" } } // Install // npm i eslint-plugin-redundant-undefined @typescript-eslint/parser eslint --save-dev // Example code that will be flagged: // function f(s?: string | undefined): void {}

Debug

Known issues

gotchaRule only works with `@typescript-eslint/parser`; using default ESLint parser will cause parsing errors.

fix

Set parser to '@typescript-eslint/parser' in ESLint config.

affects: >=1.0.0

gotchaThe rule name is 'redundant-undefined/redundant-undefined' – users often try 'redundant-undefined' alone or forget the slash.

fix

Use the full prefixed name: 'redundant-undefined/redundant-undefined'.

affects: >=1.0.0

gotchaPlugin requires ESLint >=8.46.0 and Node.js ^16.0.0 or >=18.0.0; older versions will fail to load.

fix

Update ESLint and Node.js to supported versions.

affects: >=1.0.0

gotchaOption `followExactOptionalPropertyTypes` changes the rule behavior; enabling it without having `exactOptionalPropertyTypes: true` in tsconfig may cause unexpected lint errors.

fix

Ensure TypeScript's `exactOptionalPropertyTypes` is enabled if using this option.

affects: >=1.0.0

Errors

Common errors & fixes

Error: Failed to load plugin 'redundant-undefined': Cannot find module 'eslint-plugin-redundant-undefined'

Plugin not installed or missing from node_modules.

fix

Run `npm install eslint-plugin-redundant-undefined @typescript-eslint/parser --save-dev`

Parsing error: 'parserOptions.project' has been set for @typescript-eslint/parser. The file does not match your project config: .eslintrc.json

ESLint is trying to parse the config file itself with TypeScript parser.

fix

Add `'ignorePatterns': ['.eslintrc.json']` to your ESLint config or use a .eslintrc.js file.

Error: Rule 'redundant-undefined' (or 'redundant-undefined/redundant-undefined') is not defined

Plugin not listed in 'plugins' array or rule name misspelled.

fix

Add 'redundant-undefined' to plugins and use 'redundant-undefined/redundant-undefined' as rule name.

Upgrade

Version history

1.0.0latest on npm

Audit

Dependencies

@typescript-eslint/parserrequiredPeer dependency required to parse TypeScript syntax

eslintrequiredPeer dependency; plugin is an ESLint rule

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/a-tarasyuk/eslint-plugin-redundant-undefined ↗

packagehttps://www.npmjs.com/package/eslint-plugin-redundant-undefined ↗