eslint-plugin-ext

0.1.0 verified Sat Apr 25 auth: no javascript

eslint-plugin-ext is an ESLint plugin (version 0.1.0) that provides additional lint rules, starting with 'lines-between-object-properties' which enforces blank lines between object properties, based on eslint's built-in 'lines-between-class-members'. The rule allows standard options plus an extra 'exceptBetweenSingleLines' option. The package is minimal and likely low maintenance; it is not part of a broader ecosystem and has no recent updates. It differentiates by offering a specific rule for object literals that is missing from core ESLint.

Common errors

error Error: Failed to load plugin 'ext' declared in '.eslintrc.json': Cannot find module 'eslint-plugin-ext' ↓

cause Package not installed, or wrong plugin name in ESLint config.

fix

Run 'npm install eslint-plugin-ext --save-dev' and ensure 'plugins' array uses 'ext' (without prefix).

error Configuration for rule 'ext/lines-between-object-properties' is invalid: Unknown option 'exceptBetweenSingleLines' ↓

cause The option was misspelled or placed at wrong level.

fix

Use 'exceptBetweenSingleLines' (note: 'single' not 'single'). Option must be inside an object as third element of the array.

error ESLint couldn't find the plugin 'eslint-plugin-ext' in the configuration. ↓

cause Using full package name in plugins array.

fix

Change 'plugins' to ["ext"] (omit 'eslint-plugin-' prefix).

Warnings

gotcha Plugin must be configured in ESLint's 'plugins' array, not 'extends' or 'rules' directly. ↓

fix Add 'plugins: ["ext"]' to your ESLint configuration.

gotcha Rule name must be prefixed with 'ext/'. Using just 'lines-between-object-properties' will not work. ↓

fix Use 'ext/lines-between-object-properties' as the rule key.

gotcha The 'exceptBetweenSingleLines' option is specific to this plugin and not available in ESLint core. ↓

fix Ensure this option is only used with this plugin's rule.

deprecated ESLint flat config (eslint.config.js) does not support the legacy 'plugins' array format. This plugin may not be compatible with flat config. ↓

fix Use legacy .eslintrc format or check plugin documentation for flat config support.

Install

npm install eslint-plugin-ext

yarn add eslint-plugin-ext

pnpm add eslint-plugin-ext

Imports

eslint-plugin-ext (plugin)
wrong
```
plugins: ['eslint-plugin-ext']
```
correct
```
plugins: ['ext']
```
ESLint plugin naming convention: omit the 'eslint-plugin-' prefix. This is required for ESLint to resolve the plugin.
lines-between-object-properties rule
wrong
```
"lines-between-object-properties": "error"
```
correct
```
"ext/lines-between-object-properties": ["error", "always", { "exceptBetweenSingleLines": true }]
```
Rules must be namespaced with the plugin name (ext/). Missing the namespace is the most common mistake.

ESLint config (JSON)

wrong

{
  "plugins": ["eslint-plugin-ext"],
  "rules": {
    "lines-between-object-properties": "error"
  }
}

correct

{
  "plugins": ["ext"],
  "rules": {
    "ext/lines-between-object-properties": ["error", "always"]
  }
}

Common mistake: using full package name in plugins array and not prefixing the rule with 'ext/'.

Quickstart

Shows how to configure the plugin in .eslintrc.json and demonstrates the rule behavior with bad/good object examples.

// .eslintrc.json
{
  "plugins": ["ext"],
  "rules": {
    "ext/lines-between-object-properties": ["error", "always", { "exceptBetweenSingleLines": true }]
  }
}

// Example object (bad): no blank lines between properties
export const bad = {
  a: 1,
  b: 2,
  c() {}
}

// Example object (good): blank lines between logical groups
export const good = {
  a: 1,
  b: 2,

  c() {}
}