eslint-plugin-fp

library2.3.0jsnpmunverified

ESLint plugin with 18 rules enforcing functional programming style in JavaScript. Version 2.3.0 is the latest (2017), with no new releases since. It forbids imperative constructs like loops, mutation, classes, this, and null. Differentiates from eslint-plugin-functional by broader rule set and stricter defaults. Works with ESLint >=3 and Node >=4.

testing

npm install eslint-plugin-fp

github ↗package ↗

INSTALL

IMPORT

SIG · ESLINT-PLUGIN-FP

eslint-plugin-fp

testingjavascriptv2.3.0

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.

recommended config

✓ extends: ['plugin:fp/recommended']

✗ extends: 'eslint-plugin-fp/recommended'

Use plugin:fp prefix when extending.

rules

✓ import from ESLint config; require('eslint-plugin-fp') is not needed directly

✗ const fpPlugin = require('eslint-plugin-fp')

Rules are accessed via ESLint's plugin system, not directly imported.

single rules

✓ rules: { 'fp/no-let': 'error' }

✗ rules: { 'no-let': 'error' }

Rule names must be prefixed with fp/.

Shows how to configure eslint-plugin-fp with recommended config and enable additional rules.

// Install: npm install --save-dev eslint eslint-plugin-fp // .eslintrc.json { "plugins": ["fp"], "extends": "plugin:fp/recommended", "rules": { "fp/no-let": "error", "fp/no-loops": "error", "fp/no-mutation": "error" } }

Debug

Known issues

deprecatedPlugin is no longer actively maintained; last release 2017.

fix

Consider eslint-plugin-functional or eslint-plugin-ramda for maintained alternatives.

affects: >=2.0.0

gotchaRules are very strict and may conflict with common patterns like array methods (mutating methods rule flags .sort, .reverse).

fix

Use only functional array methods and avoid mutating methods.

affects: >=1.0.0

gotchaThe no-nil rule forbids both null and undefined, which can break code relying on undefined checks.

fix

Use Maybe/Option patterns or disable the rule.

affects: >=1.0.0

Errors

Common errors & fixes

ESLint couldn't find the plugin "eslint-plugin-fp".

Plugin not installed or not properly referenced in plugins array.

fix

Run npm install --save-dev eslint-plugin-fp and ensure it's listed in plugins: ["fp"].

Definition for rule 'fp/no-let' was not found.

Rule name misspelled or plugin not loaded.

fix

Check that plugin is in plugins array and rule name is exactly 'fp/no-let'.

Configuration for rule "fp/no-mutation" is invalid.

Rule configuration uses wrong format.

fix

Use 'error' or ['error', options] not just options.

Upgrade

Version history

2.3.0latest on npm

Audit

Dependencies

eslintrequiredpeer dependency required to run the plugin

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/jfmengels/eslint-plugin-fp ↗

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