electron/docs/development/build-system-overview.md

Build System Overview

Electron uses GN for project generation and ninja for building. Project configurations can be found in the .gn and .gni files.

GN Files

The following gn files contain the main rules for building Electron:

• BUILD.gn defines how Electron itself is built and includes the default configurations for linking with Chromium.
• build/args/{debug,release,all}.gn contain the default build arguments for building Electron.

Component Build

Since Chromium is quite a large project, the final linking stage can take quite a few minutes, which makes it hard for development. In order to solve this, Chromium introduced the "component build", which builds each component as a separate shared library, making linking very quick but sacrificing file size and performance.

Electron inherits this build option from Chromium. In Debug builds, the binary will be linked to a shared library version of Chromium's components to achieve fast linking time; for Release builds, the binary will be linked to the static library versions, so we can have the best possible binary size and performance.

Tests

NB this section is out of date and contains information that is no longer relevant to the GN-built electron.

Test your changes conform to the project coding style using:

$ npm run lint

Test functionality using:

$ npm test

Whenever you make changes to Electron source code, you'll need to re-run the build before the tests:

$ npm run build && npm test

You can make the test suite run faster by isolating the specific test or block you're currently working on using Mocha's exclusive tests feature. Append .only to any describe or it function call:

describe.only('some feature', () => {
  // ... only tests in this block will be run
})

Alternatively, you can use mocha's grep option to only run tests matching the given regular expression pattern:

$ npm test -- --grep child_process

Tests that include native modules (e.g. runas) can't be executed with the debug build (see #2558 for details), but they will work with the release build.

To run the tests with the release build use:

$ npm test -- -R