Eslint rule to put a new line inside import

Question

The rule that I'm looking should show error in this case:

import {MY_CONSTANT1, MY_CONSTANT2, MY_CONSTANT3}

And considered as fine in this case:

import {
   MY_CONSTANT1, 
   MY_CONSTANT2, 
   MY_CONSTANT3
}

Is there such eslint rule?

Answer 1

I was looking for such a rule for both import and export declaration. As a result I've made a plugin with autofix.

So plugin transforms the code

import { k1, k2 } from 'something'

into

import {
  k1,
  k2
} from 'something'

and code

export { name1, name2, nameN }

into

export {
  name1,
  name2,
  nameN
}

Answer 2

Edit:

Anton Antonov made a plugin that enforces this rule better than object-curly-newline can: https://stackoverflow.com/a/60477269/6179417

---

Old answer

Add the object-curly-newline rule to your .eslintrc.json, where at least ImportDeclaration is set to always (the other settings have no effect for enforcing newlines in import declarations).

Example:

"object-curly-newline": ["error", {
   "ObjectExpression": "always",
   "ObjectPattern": { "multiline": true },
   "ImportDeclaration": "always",
   "ExportDeclaration": { "multiline": true, "minProperties": 3 }
}]

This pattern will now result in an error:

While this is valid:

However, there is a catch - this rule only requires newlines after the opening brace and before the closing brace, so you can still double up on imports as long as they have newlines in between the braces:

Answer 3

Update on Anton Antonov answer for eslint 8

Because Anton Antonovs repository has been archived and gives meta.fixable error with eslint 8. I Recommend to use ruudandriessen fork of the project .

How to use fork:

1. Install fork

npm install eslint-plugin-modules-newlines --save-dev

2. Change all references inside eslint config file of modules-newline -> modules-newlines

Error:

ESLint: Fixable rules must set the `meta.fixable` property to "code" or "whitespace".
Occurred while linting ... Rule: "modules-newline/import-declaration-newline".
Please see the 'ESLint' output channel for details.