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codeql-action/node_modules/eslint-plugin-import/docs/rules/namespace.md
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# import/namespace | |
💼 This rule is enabled in the following configs: ❗ `errors`, ☑️ `recommended`. | |
<!-- end auto-generated rule header --> | |
Enforces names exist at the time they are dereferenced, when imported as a full namespace (i.e. `import * as foo from './foo'; foo.bar();` will report if `bar` is not exported by `./foo`.). | |
Will report at the import declaration if there are _no_ exported names found. | |
Also, will report for computed references (i.e. `foo["bar"]()`). | |
Reports on assignment to a member of an imported namespace. | |
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 | |
Currently, this rule does not check for possible | |
redefinition of the namespace in an intermediate scope. Adherence to the ESLint | |
`no-shadow` rule for namespaces will prevent this from being a problem. | |
For [ES7], reports if an exported namespace would be empty (no names exported from the referenced module.) | |
Given: | |
```js | |
// @module ./named-exports | |
export const a = 1 | |
const b = 2 | |
export { b } | |
const c = 3 | |
export { c as d } | |
export class ExportedClass { } | |
// ES7 | |
export * as deep from './deep' | |
``` | |
and: | |
```js | |
// @module ./deep | |
export const e = "MC2" | |
``` | |
See what is valid and reported: | |
```js | |
// @module ./foo | |
import * as names from './named-exports' | |
function great() { | |
return names.a + names.b // so great https://youtu.be/ei7mb8UxEl8 | |
} | |
function notGreat() { | |
doSomethingWith(names.c) // Reported: 'c' not found in imported namespace 'names'. | |
const { a, b, c } = names // also reported, only for 'c' | |
} | |
// also tunnels through re-exported namespaces! | |
function deepTrouble() { | |
doSomethingWith(names.deep.e) // fine | |
doSomethingWith(names.deep.f) // Reported: 'f' not found in deeply imported namespace 'names.deep'. | |
} | |
``` | |
### Options | |
#### `allowComputed` | |
Defaults to `false`. When false, will report the following: | |
```js | |
/*eslint import/namespace: [2, { allowComputed: false }]*/ | |
import * as a from './a' | |
function f(x) { | |
return a[x] // Unable to validate computed reference to imported namespace 'a'. | |
} | |
``` | |
When set to `true`, the above computed namespace member reference is allowed, but | |
still can't be statically analyzed any further. | |
## 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 |