Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/magic-akari/swc_mut_cjs_exports
[SWC plugin] mutable CJS exports
https://github.com/magic-akari/swc_mut_cjs_exports
cjs commonjs jest swc swc-plugin
Last synced: 1 day ago
JSON representation
[SWC plugin] mutable CJS exports
- Host: GitHub
- URL: https://github.com/magic-akari/swc_mut_cjs_exports
- Owner: magic-akari
- License: mit
- Created: 2022-07-14T17:13:51.000Z (over 2 years ago)
- Default Branch: master
- Last Pushed: 2024-05-01T01:50:05.000Z (9 months ago)
- Last Synced: 2024-05-02T05:14:28.519Z (9 months ago)
- Topics: cjs, commonjs, jest, swc, swc-plugin
- Language: Rust
- Homepage: https://www.npmjs.com/package/swc_mut_cjs_exports
- Size: 477 KB
- Stars: 52
- Watchers: 2
- Forks: 13
- Open Issues: 10
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# [SWC plugin] mutable CJS exports
[](https://crates.io/crates/swc_mut_cjs_exports)
[](https://www.npmjs.com/package/swc_mut_cjs_exports)
[](https://github.com/magic-akari/swc_mut_cjs_exports/actions/workflows/test.yml)
[](https://github.com/magic-akari/swc_mut_cjs_exports/actions/workflows/swc-compat-test.yml)
[](https://github.com/magic-akari/swc_mut_cjs_exports/actions/workflows/cron-latest.yml)
[](https://github.com/magic-akari/swc_mut_cjs_exports/actions/workflows/cron-nightly.yml)
This is a SWC plugin to emit mutable CJS exports.
This SWC plugin has only been tested for compatibility with jest. It should be used with `@swc/jest`.
This project was previously called jest_workaround
## plugin version
https://swc.rs/docs/plugin/selecting-swc-core
## usage
install
```bash
npm i -D jest @swc/core @swc/jest swc_mut_cjs_exports
```
```js
// jest.config.js
const fs = require("node:fs");
const swcrc = JSON.parse(fs.readFileSync(".swcrc", "utf8"));
// If you have other plugins, change this line.
((swcrc.jsc ??= {}).experimental ??= {}).plugins = [
["swc_mut_cjs_exports", {}],
];
module.exports = {
transform: {
"^.+\\.(t|j)sx?$": ["@swc/jest", swcrc],
},
};
```
Alternative implementation without .swcrc file
```JavaScript
// jest.config.js
module.exports = {
transform: {
"^.+\\.(t|j)sx?$": [
"@swc/jest",
{
jsc: {
experimental: {
plugins: [["swc_mut_cjs_exports", {}]],
},
},
},
],
},
};
```
Make sure that `module.type` is `commonjs` in your `.swcrc` since this plugin
does not touch non-workaround parts, such as import statements.
## FAQ
#### 1. When do I need this?
If you're using the swc compiler to transform your code to comply with the ESM
specification, but you're also using Jest to test it in a CJS environment, you
may encounter issues due to the immutable issue of `exports`.
This plugin can help by transforming the `export` statements into mutable
`exports`.
#### 2. Do I have a better choice?
You may have other options depending on your specific needs:
- If you're able to run Jest in an ESM environment, you can use swc to transpile
TypeScript/JSX syntax or downgrade JavaScript syntax without module
conversion. Simply set the value of `module.type` to `es6` to achieve this.
- It's possible that some issues related to running Jest in an ESM environment
will be resolved over time. Keep an eye on
[facebook/jest#9430](https://github.com/facebook/jest/issues/9430) for
updates.
- If you don't need the behavior of ESM specifically, you can stick with the CJS
syntax to get the CJS behavior of `exports`.
These options may be worth considering before using this plugin.
CJS syntax
```JavaScript
exports.foo = function foo() {
return 42;
};
```
CTS(CJS in TypeScript) syntax
```TypeScript
export = {
foo: function foo() {
return 42;
},
};
```
Notes:
- ESM style export means immutable exports when transformed into CJS
- ESM style import means hoisted require when transformed into CJS
#### 3. After upgrading the plugin version, the changes have not taken effect.
This is a known issue. You could remove the Jest cache by running
[`jest --clearCache`](https://jestjs.io/docs/cli#--clearcache) as a workaround.