Development and Contributing

Read the Why document to get an idea as to how I’m approaching this project.

First: One Simple Rule

A simple ground rule: Extraterm is intended to be an open source project, and not just open source code. This means that all contributors need to be able get along together and cooperate on a basic level in a productive and civil way. If you can stick to this rule then you are welcome to this project.


Extraterm is built on the following technologies:

  • Electron - A platform for running desktop applications made using web technologies.
  • TypeScript - superset of JavaScript which adds static typing.
  • term.js - Terminal emulator component, pulled into the Extraterm code base and heavily modified.
  • node-pty - PTY support for node.js.
  • Ace editor - A fork of the Ace editor is using inside Extraterm. It has mostly been converted to TypeScript and modified to suit Extraterm. The fork is here.
  • … plus many other smaller libraries.

Thanks go out to the people and organisations responsible for the great software and tools I’ve been able to build on.

Running from Source

Getting started from source:

Note: Run these commands from a terminal which isn’t Extraterm < v0.30.0. (An environment variable is set inside every extraterm session which confuses node-sass when building from source, namely in the yarn install step. This problem is fixed in Extraterm 0.30.0 though.)

Extraterm uses yarn for package management. It is easiest to have it available in your path or just globally. Ensure you have a recent version (1.12 or later).

Extraterm also uses a couple of native code based modules. To successfully install these you first need to have a suitable compiler installed:

  • Linux - A recent GCC C/C++ compiler is enough. If you are on Debian based Linux distribution then installing the build-essential package will pull in the right build tools.
  • macOS - Make sure you have the Xcode compilers installed.
  • Windows - Microsoft’s C/C++ compilers need to be installed. The easiest solution is to go to windows-build-tools and follow the directions there to easily download and install the needed tools. Also the Windows SDK needs to be installed. It can be downloaded from the link or if you are using Chocolately to install software then this command will install it: choco install windows-sdk-10-version-1803-all

Once the requirements above are in place, execute these steps:

  • Clone the repository from github to your local machine.
  • Use node version 12.8.1.
  • Install the modules: yarn install.
  • Fix up the binary modules to work inside Electron: yarn run electron-rebuild or if you are on Windows yarn run electron-rebuild-win32
  • Build it: yarn run build
  • Run it: yarn run run

Code Layout

In the root of the git repository we have:

  • build_scripts - Extra scripts used for building the software and creating packages.
  • docs - Documentation and the contents of the website.
  • extensions - Extensions/plugins which are loaded by Extraterm at start up.
  • extraterm - The main application.
    • resources - Extra resource files which are need by the main application.
    • src - The source code of the main application.
  • packages - Separate modules of code which are used by the main application and extensions but is otherwise independent.

Submitting Changes

  • Bugs and features requests go in the github issue tracker.
  • Use Pull Requests to submit changes.
  • Discuss large changes via an issue in the tracker before hand.

Regular good contributors will be given direct access to the repo. I want to get the bus factor for this project above 1.

Code Formatting

The basic rule is just follow the formatting already being used in existing code. Sorry, it is not as consistent as it should be.

  • Indents are 2 spaces.
  • semi-colons are required.
  • Use exact comparisons, === and !==.
  • Prefer null over undefined.
  • Be explicit about showing what the code means. No cute shortcuts.

Updating the Version of Electron used

See this document

Road Map

Keep an eye on these places for information and speculation about future development: