Skeleton for Google Chrome extensions

• includes awesome messaging module
• webpack-based build system
• full ES6 support with Babel 6
• linting using eslint with airbnb configuration
• use node.js libraries
• unit-tests in mocha
• CircleCI friendly

Installation:

git clone git@github.com:salsita/chrome-extension-skeleton.git

# in case you don't have webpack yet:
sudo npm install -g webpack

Build instructions:

To install dependencies:

cd chrome-extension-skeleton
npm install

Then to start a developing session (with watch), run:

npm start

To start a unit testing session (with watch):

npm test

To check code for linting errors:

npm run lint

To build production code + crx:

npm run build

To run unit tests in CI scripts:

npm run test:ci

Directory structure:

/build             # this is where your extension (.crx) will end up,
                   # along with unpacked directories of production and
                   # develop build (for debugging)

/src
    /css           # CSS files
    /html          # HTML files
    /images        # image resources

    /js            # entry-points for browserify, requiring node.js `modules`

        /libs      # 3rd party run-time libraries, excluded from JS-linting
        /modules   # node.js modules (and corresponding mocha
                   #   unit tests spec files)

    manifest.json  # skeleton manifest file, `name`, `description`
                   #   and `version` fields copied from `package.json`       

/webpack           # webpack configuration files

.babelrc           # Babel configuration
.eslintrc          # options for JS-linting
circle.yml         # integration with CircleCI
mykey.pem          # certificate file, YOU NEED TO GENERATE THIS FILE, see below
package.json       # project description file (name, version, dependencies, ...)

After you clone:

1. In package.json, rename the project, description, version, add dependencies and any other fields necessary.

2. Generate your .pem key and store it in the root as mykey.pem file. On unix / mac, the command to generate the file is openssl genrsa 2048 | openssl pkcs8 -topk8 -nocrypt > mykey.pem. Note: the generated file is in .gitignore file, it won't be (and should NOT be) commited to the repository unless you know what you are doing.

3. Add content (HTML, CSS, images, JS modules), update code/manifest.json, leave only JS entry-points you use (remove the ones you don't need).

4. When developing, write unit-tests, use npm test to check that your code passes unit-tests and npm run lint to check for linting errors.

5. When ready to try out the extension in the browser, use npm start to build it. In build directory you'll find develop version of the extension in dev subdirectory (with source maps), and production (uglified) version in prod directory. The .crx packed version is created from prod sources.

6. When done developing, publish the extension and enjoy it (profit!).

Use any 3rd party libraries you need (both for run-time and for development / testing), use regular npm node.js modules (that will be installed into node_modules directory). These libraries will be encapsulated in the resulting code and will NOT conflict even with libraries on pages where you inject the resulting JS scripts to (for content scripts).

For more information, please check also README.md files in subdirectories.

Under the hood:

If you want to understand better the structure of the code and how it really works, please check the following sources (note: these resources are out of date, with respect to the build system and ES6):

• introductory blog post,
• blog post on messaging system,
• or this overall prezi.