github-pages-deploy-action/node_modules/eslint-plugin-import/docs/rules/default.md

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2020-03-07 11:45:40 +08:00
# import/default
If a default import is requested, this rule will report if there is no default
export in the imported module.
For [ES7], reports if a default is named and exported but is not found in the
referenced module.
Note: for packages, the plugin will find exported names
from [`jsnext:main`], if present in `package.json`.
Redux's npm module includes this key, and thereby is lintable, for example.
A module path that is [ignored] or not [unambiguously an ES module] will not be reported when imported.
[ignored]: ../README.md#importignore
[unambiguously an ES module]: https://github.com/bmeck/UnambiguousJavaScriptGrammar
## Rule Details
Given:
```js
// ./foo.js
export default function () { return 42 }
// ./bar.js
export function bar() { return null }
// ./baz.js
module.exports = function () { /* ... */ }
// node_modules/some-module/index.js
exports.sharedFunction = function shared() { /* ... */ }
```
The following is considered valid:
```js
import foo from './foo'
// assuming 'node_modules' are ignored (true by default)
import someModule from 'some-module'
```
...and the following cases are reported:
```js
import bar from './bar' // no default export found in ./bar
import baz from './baz' // no default export found in ./baz
```
## When Not To Use It
If you are using CommonJS and/or modifying the exported namespace of any module at
runtime, you will likely see false positives with this rule.
This rule currently does not interpret `module.exports = ...` as a `default` export,
either, so such a situation will be reported in the importing module.
## Further Reading
- Lee Byron's [ES7] export proposal
- [`import/ignore`] setting
- [`jsnext:main`] (Rollup)
[ES7]: https://github.com/leebyron/ecmascript-more-export-from
[`import/ignore`]: ../../README.md#importignore
[`jsnext:main`]: https://github.com/rollup/rollup/wiki/jsnext:main