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https://github.com/arnaudrinquin/babel-plugin-discard-module-references
Babel plugin to discard all code using specified imported modules
https://github.com/arnaudrinquin/babel-plugin-discard-module-references
Last synced: 2 months ago
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Babel plugin to discard all code using specified imported modules
- Host: GitHub
- URL: https://github.com/arnaudrinquin/babel-plugin-discard-module-references
- Owner: ArnaudRinquin
- Created: 2016-01-13T17:55:51.000Z (almost 9 years ago)
- Default Branch: master
- Last Pushed: 2019-11-06T20:30:48.000Z (about 5 years ago)
- Last Synced: 2024-10-18T19:43:55.356Z (3 months ago)
- Language: JavaScript
- Homepage: https://www.npmjs.com/package/babel-plugin-discard-module-references
- Size: 11.7 KB
- Stars: 12
- Watchers: 3
- Forks: 2
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# babel-plugin-discard-module-references [](https://travis-ci.org/ArnaudRinquin/babel-plugin-discard-module-references)
Babel plugin to discard all code using specified imported modules.
If other imported modules are not used anymore, they are discarded as well.
## Use cases
* write your tests along your code, run them in development but discard them on production
* discard analytics code in dev mode
* _???_
## Usage
1. Install the plugin
```bash
npm i -D babel-plugin-discard-module-references
```
1. Update your `.babelrc` with plugin settings
```json
{
"presets": ["es2015"],
"plugins": [
["discard-module-references", {
"targets": [ "some-module", "./or-even/relative-path" ]
}]
]
}
```
You can restrict the plugin to specific environments (like, `NODE_ENV=production`) using babel `env` config:
```json
{
"presets": ["es2015"],
"env": {
"production": {
"plugins": [
["discard-module-references", {
"targets": [ "my-test-framework" ]
}]
]
}
}
}
```
1. ... or any config you're using, seek help from [doc](https://babeljs.io/docs/setup/)
### Whitelisting unused imports
By default, all unused module imports will be discarded, wether or not it's because you target the only code that were using them. By example, if you import `sinon` for you tests but discard all of them, `sinon` becomes useless and gets discarded as well.
There is a potential issue with that when a module has expected side effects when imported.
To whitelist a module so its import never gets discarded, simply use the `unusedWhitelist` options:
```json
{
"presets": ["es2015"],
"plugins": [
["discard-module-references", {
"targets": [ "assert" ],
"unusedWhitelist": [ "sinon" ]
}]
]
}
```
Note: unspecified `imports` such as `import 'foobar';` are kept by default as they obviously must have some expected side effects.
**Note for React with JSX**
If you're using React with JSX, you will probably need to whitelist `react`.
Explanation: When using babel with JSX, you need to have `import React from 'react'` in your files because JSX will be converted to `React.doSomething()` call. This happens after the plugin runs, as a result, the `import` will be discarded as it is seen as unused your app will fail with `React is undefined`.
Just whitelist it and you'll be fine:
```json
{
"presets": ["es2015", "react"],
"env": {
"production": {
"plugins": [
["discard-module-references", {
"targets": [ "tape" ],
"unusedWhitelist": [ "react" ]
}]
]
}
}
}
```
## Example
### Writing tests right in the tested code file
The original scenario that motivated the plugin was to be able to write tests along tested code, run them in development mode (so we don't need to run another tool, just use the code and see if it breaks) but of course remove all of them for production code.
With the following code, a production build that would use `babel-plugin-discard-module-references` with `assert` would just do the trick.
```js
import assert, { deepEqual } from 'assert';
import _ from 'lodash';
import path from 'path';
export default function add(n1, n2) {
return n1 + n2;
}
function doSomethingWithLodash() {
return _.pick({nose: 'big'}, 'nose');
}
assert(add(1, 2) === 3);
assert.equal(typeof add, 'function');
deepEqual({a:1}, {a:1});
assert(path.basename('foo/bar.html') === 'something');
```
Would be compiled to the following, where all tests are removed;
```js
'use strict';
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.default = add;
var _lodash = require('lodash');
var _lodash2 = _interopRequireDefault(_lodash);
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
function add(n1, n2) {
return n1 + n2;
}
function doSomethingWithLodash() {
return _lodash2.default.pick({ nose: 'big' }, 'nose');
}
```
Note how the import of `path` has been discarded.