Add import-style rule (#789)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

docs/rules/import-style.md

@@ -0,0 +1,93 @@
+# Enforce specific import styles per module
+
+Sometimes a module contains unrelated functions, like `util`, thus it is a good practice to enforce destructuring or named imports here. Other times, in modules like `path`, it is good to use default import as they have similar functions, all likely to be utilized.
+
+This rule defines 4 import styles:
+- `unassigned` - `import 'foo'` or `require('foo')`
+- `default` - `import path from 'path'` or `const path = require('path')`
+- `namespace` - `import * as path from 'path'` or `const path = require('path')`
+- `named` - `import {inspect} from 'util'` or `const {inspect} = require('util')`
+
+## Fail
+
+```js
+const util = require('util');
+
+import util from 'util';
+
+import * as util from 'util';
+```
+
+## Pass
+
+```js
+const {promisify} = require('util');
+
+import {promisify} from 'util';
+```
+
+## Options
+
+### styles
+
+Type: `object`
+
+You can extend default import styles per module by passing the `styles` option.
+
+Default options per module are:
+- `util` - `named` only
+- `path` - `default` only
+- `chalk` - `default` only
+
+The example below:
+- Disables any restrictions on the `util` module imports.
+- Allows `named` import (leaving `default` allowed too) from the `path` module (by default only `default` import of `path` is allowed).
+
+```js
+"unicorn/import-style": [
+	"error",
+	{
+		"styles": {
+			"util": false,
+			"path": {
+				"named": true
+			}
+		}
+	}
+]
+```
+
+### extendDefaultStyles
+
+Type: `boolean`\
+Default: `true`
+
+Pass `"extendDefaultStyles": false` to override the default `styles` option completely.
+
+### checkImport
+
+Type: `boolean`\
+Default: `true`
+
+Pass `"checkImport": false` to disable linting of static import statements (like `import ... from 'foo'` or `import 'foo'`) completely.
+
+### checkDynamicImport
+
+Type: `boolean`\
+Default: `true`
+
+Pass `"checkDynamicImport": false` to disable linting of dynamic import statements (like `await import('foo')`) completely.
+
+### checkExportFrom
+
+Type: `boolean`\
+Default: `false`
+
+Pass `"checkExportFrom": true` to enable linting of export-from statements (like `export ... from 'foo'`).
+
+### checkRequire
+
+Type: `boolean`\
+Default: `true`
+
+Pass `"checkRequire": false` to disable linting of `require` calls completely.

index.js

@@ -27,6 +27,7 @@ module.exports = {
 				'unicorn/explicit-length-check': 'error',
 				'unicorn/filename-case': 'error',
 				'unicorn/import-index': 'error',
+				'unicorn/import-style': 'error',
 				'unicorn/new-for-builtins': 'error',
 				'unicorn/no-abusive-eslint-disable': 'error',
 				'unicorn/no-array-instanceof': 'error',

package.json

@@ -36,7 +36,7 @@
 		"ci-info": "^2.0.0",
 		"clean-regexp": "^1.0.0",
 		"eslint-ast-utils": "^1.1.0",
-		"eslint-template-visitor": "^2.0.0",
+		"eslint-template-visitor": "^2.2.1",
 		"eslint-utils": "^2.1.0",
 		"import-modules": "^2.0.0",
 		"lodash": "^4.17.15",

readme.md

@@ -43,6 +43,7 @@ Configure it in `package.json`.
 			"unicorn/explicit-length-check": "error",
 			"unicorn/filename-case": "error",
 			"unicorn/import-index": "error",
+			"unicorn/import-style": "error",
 			"unicorn/new-for-builtins": "error",
 			"unicorn/no-abusive-eslint-disable": "error",
 			"unicorn/no-array-instanceof": "error",
@@ -106,6 +107,7 @@ Configure it in `package.json`.
 - [explicit-length-check](docs/rules/explicit-length-check.md) - Enforce explicitly comparing the `length` property of a value. *(partly fixable)*
 - [filename-case](docs/rules/filename-case.md) - Enforce a case style for filenames.
 - [import-index](docs/rules/import-index.md) - Enforce importing index files with `.`. *(fixable)*
+- [import-style](docs/rules/import-style.md) - Enforce specific import styles per module.
 - [new-for-builtins](docs/rules/new-for-builtins.md) - Enforce the use of `new` for all builtins, except `String`, `Number`, `Boolean`, `Symbol` and `BigInt`. *(fixable)*
 - [no-abusive-eslint-disable](docs/rules/no-abusive-eslint-disable.md) - Enforce specifying rules to disable in `eslint-disable` comments.
 - [no-array-instanceof](docs/rules/no-array-instanceof.md) - Require `Array.isArray()` instead of `instanceof Array`. *(fixable)*