Sorting your imports with ESLint

#eslint #import #javascript #react

On files that use a lot of resources, imports can become a mess. Enforcing styles and patterns can be helpful, however, doing that manually doesn't seem to be the best use of time.

Fortunately, nowadays there are some amazing tools out there that can help us keep our imports organized automatically.

For this article, we will be using eslint-plugin-simple-import-sort. This is an ESLint plugin that enables not only sorting with some nice defaults but also grouping based on defined patterns.

The target

Let's take for the following code:

// an import using an alias path
import { Header, Card } from 'components';
// an import from a package that we want to always see first
import React, { useState } from 'react';
// an ui package
import { Button } from 'ui-package';
// a relative import that is in the same folder
import { parseTableData } from './utils';
// a relative import that is up in the tree
import { generatePath } from '../../domain';

The organization we would like to enforce is:

The "react" import should always come first
Package imports should come next, sorted by alphabetical order
The named imports should be sorted in alphabetical order
It should skip a line before relative imports that are in other folders
It should skip a line before the imports that are in the current folder

Set up

To set up the plugin, first, it's needed to have ESLint integrated into your project.

The first step is installing the plugin:

yarn install eslint-plugin-simple-import-sort

Then, in your ESLint config file (.eslintrc.json) add the plugin in the "plugins" list.

# eslintrc.json

{
  "plugins": ["react", "simple-import-sort"], 
  "rules": {
    // increase the severity of rules so they are auto-fixable
    "simple-import-sort/imports": "error",
    "simple-import-sort/exports": "error"
  }
}

This should be enough to sort the paths and the named exports alphabetically.

One step further

Now, going one step further. It's also possible to set custom groupings, so it skips lines before sets of imports.

In the ESLint config file, add the following override:

{
  "overrides": [
    // override "simple-import-sort" config
    {
      "files": ["*.js", "*.jsx", "*.ts", "*.tsx"],
      "rules": {
        "simple-import-sort/imports": [
          "error",
          {
            "groups": [
              // Packages `react` related packages come first.
              ["^react", "^@?\\w"],
              // Internal packages.
              ["^(@|components)(/.*|$)"],
              // Side effect imports.
              ["^\\u0000"],
              // Parent imports. Put `..` last.
              ["^\\.\\.(?!/?$)", "^\\.\\./?$"],
              // Other relative imports. Put same-folder imports and `.` last.
              ["^\\./(?=.*/)(?!/?$)", "^\\.(?!/?$)", "^\\./?$"],
              // Style imports.
              ["^.+\\.?(css)$"]
            ]
          }
        ]
      }
    }
  ]
}

Finish line

And you're all set! The sorting should happen automatically when ESLint is run in the auto-fix mode.

Here's the code after sorted:

import React, { useState } from 'react';
import { Card, Header } from 'components';
import { Button } from 'ui-package';

import { generatePath } from '../../domain';

import { parseTableData } from './utils';