tree: 8d41ca61af7ec566896b6fc03ab75c1075522e0f [path history] [tgz]
  1. .gitattributes
  2. .gitignore
  3. BUILD
  5. app/
  6. edit-walkthrough/
  8. server.go
  9. wct.conf.js


Installing Bazel

Follow the instructions here to get and install Bazel.

Installing Node.js and npm packages

The minimum nodejs version supported is 8.x+

# Debian experimental
sudo apt-get install nodejs-legacy
sudo apt-get install npm

# OS X with Homebrew
brew install node
brew install npm

All other platforms: download from

Various steps below require installing additional npm packages. The full list of dependencies can be installed with:

sudo npm install -g \
  eslint \
  eslint-config-google \
  eslint-plugin-html \
  typescript \
  fried-twinkie \
  polylint \

It may complain about a missing typescript@2.3.4 peer dependency, which is harmless.

If you're interested in the details, keep reading.

Local UI, Production Data

This is a quick and easy way to test your local changes against real data. Unfortunately, you can't sign in, so testing certain features will require you to use the “test data” technique described below.

Running the server

To test the local UI against


Then visit http://localhost:8081

Local UI, Test Data

One-time setup:

  1. Build Gerrit
  2. Set up a local test site. Docs here and here.

When your project is set up and works using the classic UI, run a test server that serves PolyGerrit:

bazel build polygerrit &&
  $(bazel info output_base)/external/local_jdk/bin/java \
  -jar bazel-bin/polygerrit.war daemon --polygerrit-dev \
  -d ../gerrit_testsite --console-log --show-stack-trace

Serving plugins

Local dev plugins must be put inside of gerrit/plugins

Loading a single plugin file:

./ --plugins=plugins/my_plugin/static/my_plugin.js

Loading multiple plugin files:

./ --plugins=plugins/my_plugin/static/my_plugin.js,plugins/my_plugin/static/my_plugin.html

Running Tests

This step requires the web-component-tester npm module.

Note: it may be necessary to add the options --unsafe-perm=true --allow-root to the npm install command to avoid file permission errors.

Run all web tests:


To allow the tests to run in Safari:

  • In the Advanced preferences tab, check “Show Develop menu in menu bar”.
  • In the Develop menu, enable the “Allow Remote Automation” option.

If you need to pass additional arguments to wct:

WCT_ARGS='-p --some-flag="foo bar"' ./polygerrit-ui/app/

For interactively working on a single test file, do the following:


Then visit http://localhost:8081/elements/foo/bar_test.html

To run Chrome tests in headless mode:

WCT_HEADLESS_MODE=1 ./polygerrit-ui/app/

Toolchain requirements for headless mode:

  • Chrome: 59+
  • web-component-tester: v6.5.0+

Style guide

We follow the Google JavaScript Style Guide with a few exceptions. When in doubt, remain consistent with the code around you.

In addition, we encourage the use of ESLint. It is available as a command line utility, as well as a plugin for most editors and IDEs.

eslint-config-google is a port of the Google JS Style Guide to an ESLint config module, and eslint-plugin-html allows ESLint to lint scripts inside HTML. We have an .eslintrc.json config file in the polygerrit-ui/ directory configured to enforce the preferred style of the PolyGerrit project. After installing, you can use eslint on any new file you create. In addition, you can supply the --fix flag to apply some suggested fixes for simple style issues. If you modify JS inside of <script> tags, like for test suites, you may have to supply the --ext .html flag.

Some useful commands:

  • To run ESLint on the whole app, less some dependency code: eslint --ignore-pattern 'bower_components/' --ignore-pattern 'gr-linked-text' --ignore-pattern 'scripts/vendor' --ext .html,.js polygerrit-ui/app
  • To run ESLint on just the subdirectory you modified: eslint --ext .html,.js polygerrit-ui/app/$YOUR_DIR_HERE
  • To run the linter on all of your local changes: git diff --name-only master | xargs eslint --ext .html,.js

We also use the polylint tool to lint use of Polymer. To install polylint, execute the following command.

To run polylint, execute the following command.

bazel test //polygerrit-ui/app:polylint_test

Template Type Safety

Polymer elements are not type checked against the element definition, making it trivial to break the display when refactoring or moving code. We now run additional tests to help ensure that template types are checked.

A few notes to ensure that these tests pass

  • Any functions with optional parameters will need closure annotations.
  • Any Polymer parameters that are nullable or can be multiple types (other than the one explicitly delared) will need type annotations.

These tests require the typescript and fried-twinkie npm packages.

To run on all files, execute the following command:


To run on a specific top level directory (ex: change-list)

TEMPLATE_NO_DEFAULT=true ./polygerrit-ui/app/ //polygerrit-ui/app:template_test_change-list

To run on a specific file (ex: gr-change-list-view), execute the following command:

TEMPLATE_NO_DEFAULT=true ./polygerrit-ui/app/ //polygerrit-ui/app:template_test_<TOP_LEVEL_DIRECTORY> --test_arg=<VIEW_NAME>
TEMPLATE_NO_DEFAULT=true ./polygerrit-ui/app/ //polygerrit-ui/app:template_test_change-list --test_arg=gr-change-list-view