electron/docs/development/source-code-directory-structure.md

Source Code Directory Structure

The source code of Electron is separated into a few parts, mostly following Chromium on the separation conventions.

You may need to become familiar with Chromium's multi-process architecture to understand the source code better.

Structure of Source Code

Electron
├── atom - C++ source code.
|   ├── app - System entry code.
|   ├── browser - The frontend including the main window, UI, and all of the
|   |   main process things. This talks to the renderer to manage web pages.
|   |   ├── ui - Implementation of UI stuff for different platforms.
|   |   |   ├── cocoa - Cocoa specific source code.
|   |   |   ├── gtk - GTK+ specific source code.
|   |   |   └── win - Windows GUI specific source code.
|   |   ├── api - The implementation of the main process APIs.
|   |   ├── net - Network related code.
|   |   ├── mac - Mac specific Objective-C source code.
|   |   └── resources - Icons, platform-dependent files, etc.
|   ├── renderer - Code that runs in renderer process.
|   |   └── api - The implementation of renderer process APIs.
|   └── common - Code that used by both the main and renderer processes,
|       including some utility functions and code to integrate node's message
|       loop into Chromium's message loop.
|       └── api - The implementation of common APIs, and foundations of
|           Electron's built-in modules.
├── chromium_src - Source code that copied from Chromium.
├── default_app - The default page to show when Electron is started without
|   providing an app.
├── docs - Documentations.
├── lib  - JavaScript source code.
|   ├── browser - Javascript main process initialization code.
|   |   └── api - Javascript API implementation.
|   ├── common - JavaScript used by both the main and renderer processes
|   |   └── api - Javascript API implementation.
|   └── renderer - Javascript renderer process initialization code.
|       └── api - Javascript API implementation.
├── spec - Automatic tests.
├── atom.gyp - Building rules of Electron.
└── common.gypi - Compiler specific settings and building rules for other
    components like `node` and `breakpad`.

Structure of Other Directories

• script - Scripts used for development purpose like building, packaging, testing, etc.
• tools - Helper scripts used by gyp files, unlike script, scripts put here should never be invoked by users directly.
• vendor - Source code of third party dependencies, we didn't use third_party as name because it would confuse it with the same directory in Chromium's source code tree.
• node_modules - Third party node modules used for building.
• out - Temporary output directory of ninja.
• dist - Temporary directory created by script/create-dist.py script when creating a distribution.
• external_binaries - Downloaded binaries of third-party frameworks which do not support building with gyp.