| # import/no-mutable-exports |
| |
| Forbids the use of mutable exports with `var` or `let`. |
| |
| ## Rule Details |
| |
| Valid: |
| |
| ```js |
| export const count = 1 |
| export function getCount() {} |
| export class Counter {} |
| ``` |
| |
| ...whereas here exports will be reported: |
| |
| ```js |
| export let count = 2 |
| export var count = 3 |
| |
| let count = 4 |
| export { count } // reported here |
| ``` |
| |
| ## Functions/Classes |
| |
| Note that exported function/class declaration identifiers may be reassigned, |
| but are not flagged by this rule at this time. They may be in the future, if a |
| reassignment is detected, i.e. |
| |
| ```js |
| // possible future behavior! |
| export class Counter {} // reported here: exported class is reassigned on line [x]. |
| Counter = KitchenSink // not reported here unless you enable no-class-assign |
| |
| // this pre-declaration reassignment is valid on account of function hoisting |
| getCount = function getDuke() {} // not reported here without no-func-assign |
| export function getCount() {} // reported here: exported function is reassigned on line [x]. |
| ``` |
| |
| To prevent general reassignment of these identifiers, exported or not, you may |
| want to enable the following core ESLint rules: |
| |
| - [no-func-assign] |
| - [no-class-assign] |
| |
| [no-func-assign]: https://eslint.org/docs/rules/no-func-assign |
| [no-class-assign]: https://eslint.org/docs/rules/no-class-assign |
| |
| ## When Not To Use It |
| |
| If your environment correctly implements mutable export bindings. |