Development Setup

IDE

When developing Flipper plugins we recommend the following IDEs:

  1. TypeScript (for Flipper Desktop (plugins)): Visual Studio Code

    1. Install the "ESLint" (dbaeumer.vscode-eslint) extension from marketplace to enable linting
    2. Install the "Prettier" (esbenp.prettier-vscode) extension to enable automatic code-formatting
    3. If for some reason it is not working, the builtin TypeScript extension might be disabled. To enable it, to go to extensions, search for “@builtin typescript” and enable it.
  2. Android Studio (for Android plugins)

  3. XCode (for iOS plugins)

Running Flipper from source (recommended)

When developing Flipper plugins we strongly recommend to run from Flipper itself from source as well, as this yields several benefits:

  • Automatic transpilation and bundling of loaded plugins: ES6, TypeScript, JSX.
  • Automatic refresh after code changes.
  • React and Redux Dev Tools.
  • Debugging using Chrome Dev Tools or Visual Studio Code.
  • Additional debug information like React warnings and performance metrics.

Prerequisites for Flipper development build:

  • node ≥ 14
  • yarn ≥ 1.5
  • git
  • watchman

To run Flipper Desktop from source:

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

Tip: start with yarn start --fast-refresh for experimental fast refresh.

Startup options

You can use several options to customise development build instance. They can be provided as command-line args or environment variables. You can check all of them by executing yarn start --help:

yarn start [args]
Options:
--embedded-plugins Enables embedding of plugins into Flipper bundle. If it
disabled then only installed plugins are loaded. The
flag is enabled by default. Env var
FLIPPER_NO_EMBEDDED_PLUGINS is equivalent to the
command-line option "--no-embedded-plugins". [boolean]
--fast-refresh Enable Fast Refresh - quick reload of UI component
changes without restarting Flipper. The flag is disabled
by default. Env var FLIPPER_FAST_REFRESH is equivalent
to the command-line option "--fast-refresh". [boolean]
--plugin-auto-update [FB-internal only] Enable plugin auto-updates. The flag
is disabled by default in dev mode. Env var
FLIPPER_NO_PLUGIN_AUTO_UPDATE is equivalent to the
command-line option "--no-plugin-auto-update" [boolean]
--enabled-plugins Load only specified plugins and skip loading rest. This
is useful when you are developing only one or few
plugins. Plugins to load can be specified as a
comma-separated list with either plugin id or name used
as identifier, e.g. "--enabled-plugins
network,inspector". The flag is not provided by default
which means that all plugins loaded. [array]
--open-dev-tools Open Dev Tools window on startup. The flag is disabled
by default. Env var FLIPPER_OPEN_DEV_TOOLS is equivalent
to the command-line option "--open-dev-tools". [boolean]
--dev-server-port Dev server port. 3000 by default. Env var "PORT=3001" is
equivalent to the command-line option "--dev-server-port
3001". [number] [default: 3000]
--version Show version number [boolean]
--help Show help [boolean]

You can also create file .env in desktop subfolder and specify any environment variables to load them automatically on yarn start so you don't need to pass command-line args every time, e.g.:

FLIPPER_FAST_REFRESH=true
FLIPPER_OPEN_DEV_TOOLS=true
FLIPPER_ENABLED_PLUGINS=flipper-messages,network,inspector

Guidelines for writing TypeScript

  • Important: Use .tsx file extension for all TypeScript files (instead of .ts)
  • Prefer type for React props and state over interfaces
  • Don’t prefix interfaces with I
  • Enums, Types and Interfaces use PascalCase (uppercase first letter)
  • Install 3rd party type definitions as dev dependency (e.g. yarn add @types/lodash --dev)

Submitting a diff / PR

Make sure your new functionality is covered with tests, and run yarn test or yarn test --watch in the desktop/ directory to verify that they pass.

See the testing page for more details on writing and running test.

To make sure you don't get any lint/formatting errors, run yarn lint before submitting your diff. Some errors (especially formatting errors can be auto-fixed by running yarn fix