55 lines
1.8 KiB
Markdown
55 lines
1.8 KiB
Markdown
|
# import/unambiguous
|
||
|
|
|
||
|
|
Warn if a `module` could be mistakenly parsed as a `script` by a consumer leveraging
|
||
|
|
[Unambiguous JavaScript Grammar] to determine correct parsing goal.
|
||
|
|
|
||
|
|
Will respect the [`parserOptions.sourceType`] from ESLint config, i.e. files parsed
|
||
|
|
as `script` per that setting will not be reported.
|
||
|
|
|
||
|
|
This plugin uses [Unambiguous JavaScript Grammar] internally to decide whether
|
||
|
|
dependencies should be parsed as modules and searched for exports matching the
|
||
|
|
`import`ed names, so it may be beneficial to keep this rule on even if your application
|
||
|
|
will run in an explicit `module`-only environment.
|
||
|
|
|
||
|
|
## Rule Details
|
||
|
|
|
||
|
|
For files parsed as `module` by ESLint, the following are valid:
|
||
|
|
|
||
|
|
```js
|
||
|
|
import 'foo'
|
||
|
|
function x() { return 42 }
|
||
|
|
```
|
||
|
|
|
||
|
|
```js
|
||
|
|
export function x() { return 42 }
|
||
|
|
```
|
||
|
|
|
||
|
|
```js
|
||
|
|
(function x() { return 42 })()
|
||
|
|
export {} // simple way to mark side-effects-only file as 'module' without any imports/exports
|
||
|
|
```
|
||
|
|
|
||
|
|
...whereas the following file would be reported:
|
||
|
|
```js
|
||
|
|
(function x() { return 42 })()
|
||
|
|
```
|
||
|
|
|
||
|
|
## When Not To Use It
|
||
|
|
|
||
|
|
If your application environment will always know via [some other means](https://github.com/nodejs/node-eps/issues/13)
|
||
|
|
how to parse, regardless of syntax, you may not need this rule.
|
||
|
|
|
||
|
|
Remember, though, that this plugin uses this strategy internally, so if you were
|
||
|
|
to `import` from a module with no `import`s or `export`s, this plugin would not
|
||
|
|
report it as it would not be clear whether it should be considered a `script` or
|
||
|
|
a `module`.
|
||
|
|
|
||
|
|
## Further Reading
|
||
|
|
|
||
|
|
- [Unambiguous JavaScript Grammar]
|
||
|
|
- [`parserOptions.sourceType`]
|
||
|
|
- [node-eps#13](https://github.com/nodejs/node-eps/issues/13)
|
||
|
|
|
||
|
|
[`parserOptions.sourceType`]: https://eslint.org/docs/user-guide/configuring#specifying-parser-options
|
||
|
|
[Unambiguous JavaScript Grammar]: https://github.com/nodejs/node-eps/blob/HEAD/002-es-modules.md#32-determining-if-source-is-an-es-module
|