|
|
# import/extensions - Ensure consistent use of file extension within the import path |
|
|
|
|
|
Some file resolve algorithms allow you to omit the file extension within the import source path. For example the `node` resolver can resolve `./foo/bar` to the absolute path `/User/someone/foo/bar.js` because the `.js` extension is resolved automatically by default. Depending on the resolver you can configure more extensions to get resolved automatically. |
|
|
|
|
|
In order to provide a consistent use of file extensions across your code base, this rule can enforce or disallow the use of certain file extensions. |
|
|
|
|
|
## Rule Details |
|
|
|
|
|
This rule either takes one string option, one object option, or a string and an object option. If it is the string `"never"` (the default value), then the rule forbids the use for any extension. If it is the string `"always"`, then the rule enforces the use of extensions for all import statements. If it is the string `"ignorePackages"`, then the rule enforces the use of extensions for all import statements except package imports. |
|
|
|
|
|
``` |
|
|
"import/extensions": [<severity>, "never" | "always" | "ignorePackages"] |
|
|
``` |
|
|
|
|
|
By providing an object you can configure each extension separately. |
|
|
|
|
|
``` |
|
|
"import/extensions": [<severity>, { |
|
|
<extension>: "never" | "always" | "ignorePackages" |
|
|
}] |
|
|
``` |
|
|
|
|
|
For example `{ "js": "always", "json": "never" }` would always enforce the use of the `.js` extension but never allow the use of the `.json` extension. |
|
|
|
|
|
By providing both a string and an object, the string will set the default setting for all extensions, and the object can be used to set granular overrides for specific extensions. |
|
|
|
|
|
``` |
|
|
"import/extensions": [ |
|
|
<severity>, |
|
|
"never" | "always" | "ignorePackages", |
|
|
{ |
|
|
<extension>: "never" | "always" | "ignorePackages" |
|
|
} |
|
|
] |
|
|
``` |
|
|
|
|
|
For example, `["error", "never", { "svg": "always" }]` would require that all extensions are omitted, except for "svg". |
|
|
|
|
|
`ignorePackages` can be set as a separate boolean option like this: |
|
|
``` |
|
|
"import/extensions": [ |
|
|
<severity>, |
|
|
"never" | "always" | "ignorePackages", |
|
|
{ |
|
|
ignorePackages: true | false, |
|
|
pattern: { |
|
|
<extension>: "never" | "always" | "ignorePackages" |
|
|
} |
|
|
} |
|
|
] |
|
|
``` |
|
|
In that case, if you still want to specify extensions, you can do so inside the **pattern** property. |
|
|
Default value of `ignorePackages` is `false`. |
|
|
|
|
|
|
|
|
### Exception |
|
|
|
|
|
When disallowing the use of certain extensions this rule makes an exception and allows the use of extension when the file would not be resolvable without extension. |
|
|
|
|
|
For example, given the following folder structure: |
|
|
|
|
|
``` |
|
|
├── foo |
|
|
│ ├── bar.js |
|
|
│ ├── bar.json |
|
|
``` |
|
|
|
|
|
and this import statement: |
|
|
|
|
|
```js |
|
|
import bar from './foo/bar.json'; |
|
|
``` |
|
|
|
|
|
then the extension can’t be omitted because it would then resolve to `./foo/bar.js`. |
|
|
|
|
|
### Examples |
|
|
|
|
|
The following patterns are considered problems when configuration set to "never": |
|
|
|
|
|
```js |
|
|
import foo from './foo.js'; |
|
|
|
|
|
import bar from './bar.json'; |
|
|
|
|
|
import Component from './Component.jsx'; |
|
|
|
|
|
import express from 'express/index.js'; |
|
|
``` |
|
|
|
|
|
The following patterns are not considered problems when configuration set to "never": |
|
|
|
|
|
```js |
|
|
import foo from './foo'; |
|
|
|
|
|
import bar from './bar'; |
|
|
|
|
|
import Component from './Component'; |
|
|
|
|
|
import express from 'express/index'; |
|
|
|
|
|
import * as path from 'path'; |
|
|
``` |
|
|
|
|
|
The following patterns are considered problems when configuration set to "always": |
|
|
|
|
|
```js |
|
|
import foo from './foo'; |
|
|
|
|
|
import bar from './bar'; |
|
|
|
|
|
import Component from './Component'; |
|
|
|
|
|
import foo from '@/foo'; |
|
|
``` |
|
|
|
|
|
The following patterns are not considered problems when configuration set to "always": |
|
|
|
|
|
```js |
|
|
import foo from './foo.js'; |
|
|
|
|
|
import bar from './bar.json'; |
|
|
|
|
|
import Component from './Component.jsx'; |
|
|
|
|
|
import * as path from 'path'; |
|
|
|
|
|
import foo from '@/foo.js'; |
|
|
``` |
|
|
|
|
|
The following patterns are considered problems when configuration set to "ignorePackages": |
|
|
|
|
|
```js |
|
|
import foo from './foo'; |
|
|
|
|
|
import bar from './bar'; |
|
|
|
|
|
import Component from './Component'; |
|
|
|
|
|
``` |
|
|
|
|
|
The following patterns are not considered problems when configuration set to "ignorePackages": |
|
|
|
|
|
```js |
|
|
import foo from './foo.js'; |
|
|
|
|
|
import bar from './bar.json'; |
|
|
|
|
|
import Component from './Component.jsx'; |
|
|
|
|
|
import express from 'express'; |
|
|
|
|
|
import foo from '@/foo' |
|
|
``` |
|
|
|
|
|
The following patterns are not considered problems when configuration set to `['error', 'always', {ignorePackages: true} ]`: |
|
|
|
|
|
```js |
|
|
import Component from './Component.jsx'; |
|
|
|
|
|
import baz from 'foo/baz.js'; |
|
|
|
|
|
import express from 'express'; |
|
|
|
|
|
import foo from '@/foo'; |
|
|
``` |
|
|
|
|
|
## When Not To Use It |
|
|
|
|
|
If you are not concerned about a consistent usage of file extension.
|
|
|
|