---
id: js-setup
title: JavaScript Plugin Definition
---

All JavaScript Flipper plugins consist of a directory. This directory must contain the following two files:
* package.json
* index.js

To create the desktop part of your plugin, initiate a new JavaScript project using `yarn init` and make sure your package name is the same as the identifier of the client plugin. Create a file called `index.js`, which is the entry point to your plugin. An example `package.json` file could look like this:

Example `package.json`:
```
{
  "name": "myplugin",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT",
  "dependencies": {},
  "title": "My Plugin",
  "icon": "apps",
  "bugs": {
    "email": "you@example.com"
  }
}
```

Important attributes of `package.json`:

`name` Used as the plugin identifier and **must match the mobile plugin Identifier**.

`title` Shown in the main sidebar as the human readable name of the plugin.

`icon` Determines the plugin icon which is displayed in the main sidebar.

`bugs` Specify an email and/or url, where plugin bugs should be reported.

In `index.js` you can now create your plugin. Take a look at [Writing a plugin](writing-a-plugin.md) to see what this code looks like. Also, make sure to check out the [Flipper UI Component Library](ui-components.md) for lots of pre-made components.

### Dynamically loading plugins

Flipper will load and run plugins it finds in a configurable location. The paths searched are specified in `~/.flipper/config.json`. These paths, `pluginPaths`, should contain one folder for each of the plugins it stores. An example config setting and plugin file structure is shown below:

`~/.flipper/config.json`:
```
{
  ...,
  "pluginPaths": ["~/flipper-plugins"]
}
```
Plugin File Structure:
```
~ flipper-plugins/
    my-plugin/
      package.json
      index.js
```

### npm dependencies

If you need any dependencies in your plugin, you can install them using `yarn add`. The Flipper UI components exported from `flipper`, as well as `react` and `react-dom` don't need to be installed as dependencies. Our plugin-loader makes these dependencies available to your plugin.

### ES6, babel-transforms and bundling

Our plugin-loader is capable of all ES6 goodness, flow annotations and JSX and applies the required babel-transforms without you having to care about this. Also you don't need to bundle your plugin, you can simply use ES6 imports and it will work out of the box.

## Working on the core

If you only want to work on a plugin, you don't need to run the development build of Flipper, but you can use the production release. However, if you want to contribute to Flipper's core, add additional UI components, or do anything outside the scope of a single plugins this is how you run the development version of Flipper.

Make sure you have a recent version of node.js and yarn installed on your system (node ≥ 8, yarn ≥ 1.5). Then run the following commands:

```
git clone https://github.com/facebook/flipper.git
cd flipper
yarn
yarn start
```