neutrino-dev/docs/middleware/neutrino-middleware-loader-merge/README.md

# Neutrino Loader Merge Middleware
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`neutrino-middleware-loader-merge` is Neutrino middleware for easily performing a deep merge of options into
a named rule and named loader in a Neutrino configuration.

## Requirements

- Node.js v6.9+
- Yarn or npm client
- Neutrino v5

## Installation

`neutrino-middleware-loader-merge` can be installed via the Yarn or npm clients.

#### Yarn

```bash
❯ yarn add neutrino-middleware-loader-merge
```

#### npm

```bash
❯ npm install --save neutrino-middleware-loader-merge
```

## Usage

`neutrino-middleware-loader-merge` can be consumed from the Neutrino API, middleware, or presets. Require this package
and plug it into Neutrino:

```js
const loaderMerge = require('neutrino-middleware-loader-merge');

neutrino.use(loaderMerge('compile', 'babel'), {
  plugins: ['object-rest-spread']
});

// Equivalent to:
neutrino.config.module
  .rule('compile')
  .use('babel')
    .tap(options => require('deepmerge')(options, {
      plugins: ['object-rest-spread']
    }));
```

This middleware is a factory intended to be invoked with a rule name and a loader name for which to extend the options.
Upon invoking, it will return a middleware function to be provided to Neutrino's `use()` method.

```js
const middleware = loaderMerge(ruleName, loaderName);

neutrino.use(middleware, options);
```


## Customization

`neutrino-middleware-loader-merge` does not create any of its own conventions; it is only middleware
for extending the options for a rule loader which has create its own conventions.

## Contributing

This preset is part of the [neutrino-dev](https://github.com/mozilla-neutrino/neutrino-dev) repository, a monorepo
containing all resources for developing Neutrino and its core presets. Follow the
[contributing guide](../../contributing/README.md) for details.

[npm-image]: https://img.shields.io/npm/v/neutrino-middleware-loader-merge.svg
[npm-downloads]: https://img.shields.io/npm/dt/neutrino-middleware-loader-merge.svg
[npm-url]: https://npmjs.org/package/neutrino-middleware-loader-merge
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[slack-url]: https://neutrino-slack.herokuapp.com/