The CKEditor 5 codebase is divided into multiple npm packages, each developed in a separate Git repository. The main package is ckeditor5 which installs all project dependencies and various development-related resources such as:
- the testing environment setup,
- configuration for mgit (a multi-repo management tool) and Lerna.js (a multi-package management tool),
- translation management tools,
- documentation generator,
- and release tools.
You can find all the official packages listed in CKEditor 5 development repository’s README.
In order to start developing CKEditor 5 you will require:
# Setting up the CKEditor development environment
First, you need to install a couple of tools which you will be using later:
It is best to install them globally in your system for an easier use later on:
npm install -g lerna mgit2
Note: You may need to use
sudo on Linux and macOS.
Then clone the main repository:
git clone https://github.com/ckeditor/ckeditor5.git cd ckeditor5
And install all CKEditor 5 packages from the npm registry.
Note: If you plan to use the developement version of CKEditor 5 packages (see the next section), you can skip this step to save time.
This may take a while…
# Switching to development version of packages
The above steps should install all the packages from npm, which means that you will have the latest releases of all of them. They are available in
node_modules/@ckeditor/ (we are using scoped packages, hence the unusual directory).
In order to work with development versions of all the official packages, it is recommended to use mgit and Lerna. The former will clone all package repositories and the latter will be able to symlink them, so they create a correct directory structure, understandable by Node.js-compliant tools (like webpack or Browserify).
First, clone all the repositories:
(master 340feac) p@m /workspace/ckeditor5> tree -L 1 packages/ packages/ ├── ckeditor5-autoformat ├── ckeditor5-basic-styles ├── ckeditor5-clipboard ... └── ckeditor5-utils
Finally, link them:
Running Lerna may take a while because it installs all package dependencies. It will also warn you about circular dependencies between packages which you can ignore.
Now, all CKEditor packages (except the dev tools) should be cross-symlinked:
(master 340feac) p@m /workspace/ckeditor5> ls -la node_modules/\@ckeditor/ckeditor5-utils/node_modules/\@ckeditor/ total 16 drwxr-xr-x 5 p staff 170 31 Jan 10:37 . drwxr-xr-x 292 p staff 9928 20 Jan 00:20 .. lrwxr-xr-x 1 p staff 23 31 Jan 10:37 ckeditor5-core -> ../../../ckeditor5-core drwxr-xr-x 7 p staff 238 20 Jan 00:20 ckeditor5-dev-docs lrwxr-xr-x 1 p staff 25 31 Jan 10:37 ckeditor5-engine -> ../../../ckeditor5-engine
If everything worked correctly, you should be able to run some tests:
npm run test -- --files=core
# Fetching changes
Whenever you want to update all packages to their latest versions call:
# To update the ckeditor5 repository itself: git pull # To update pull changes to all the packages: mgit update
From time to time, if the list of dependencies in any of the packages changed, you will need to call Lerna again to symlink them:
You can also speed it up if you know which package has changed:
lerna bootstrap --scope=@ckeditor/ckeditor5-core
# Using mgit for custom packages
If you are developing custom packages or forked any of the official packages and want mgit to work with it, change the dependencies configuration in
mgit.json. Note that mgit is able to clone the package from any Git URL. Refer to its documentation for more details.
# Troubleshooting problems with Lerna
Lerna does pretty complicated things on already complicated npm ecosystem. If you happen to run into some issues when calling
lerna bootstrap, here are some tips:
- Look for
npm-debug.logfiles in the main package and subpackages. They may point to an obvious issue like a typo in some
- Sometimes repeating
lerna bootstrapmay help.
- If nothing else works, do
lerna clean && lerna bootstrap.
# Final word about mgit and Lerna
Lerna is a tool used by many well-known projects such as Babel.js. It has an amazing community and, relying on it ourselves, we hope that it will become a standard for managing multi-package projects.
# Running tests
In order to run tests you need to use the
npm test -- --watch --coverage --source-map --files=engine
npm test -- -wcs --files=engine
This command will run the
ckeditor5-engine package’s tests.
Note: It is not possible to run tests of all packages with code coverage at once because the size of the project (the number of test files and source modules) exceeds webpack’s capabilities (it runs out of memory).
To create a server for manual tests use the
npm run test:manual
It accepts the
You can read more about the Testing environment.
# Generating documentation
To build the documentation you need to run the
npm run docs
The documentation will be available in
This task accepts two arguments which can speed up the process:
--skip-api– Skips building API docs (which takes the majority of the total time).
--skip-snippets– Skips building live snippets.
--skip-validation– Skips the final links validation.
Note: These arguments must be passed after additional
npm run docs -- --skip-api.
# Bisecting through a multi-repository
CKEditor 5 is a multi-repository project. It means that
git bisect (which is super handy when tracking which commit introduced a bug) will not work out of the box.
Fortunately, every commit made to any of
master branches of all CKEditor 5 subpackages will update this subpackage’s hash in
mgit.json in the
Thanks to that,
master-revisions contains an ordered history of all changes which makes it possible to go back to any point in history:
# Make sure to update this branch. git co master-revisions git pull # Check out 30 commits back. git co master-revisions~30 # Check out subpackages to correct hashes. mgit co
Once you found the point in history which interests you, you can go straight to a commit in a subpackage and PR. For example:
(detached:bisect/bad~1 cb2feef ?1) p@m /workspace/ckeditor5> git bisect good ab5b5494e5eba7beb4a3bac4ea9c5e6d59a610f5 is the first bad commit commit ab5b5494e5eba7beb4a3bac4ea9c5e6d59a610f5 Author: Travis CI User <firstname.lastname@example.org> Date: Tue Apr 11 16:45:47 2017 +0000 Revision: https://github.com/ckeditor/ckeditor5-image/commit/02869eb4478a2f538006c128b30b9727617af665 :100644 100644 611526d5c4beae7046b0a08ec36843cbbe642175 35acdd8ba971d8127dd462a9c8c1162a54f00d58 M mgit.json
# Additional information for contributors
# SVG icons
By default, CKEditor 5 supports SVG icons found in the
ckeditor5-*/theme/icons folders. Unfortunately, most of the SVG editing software produces the output with comments, obsolete tags, and complex paths, which bloats the DOM and makes the builds heavy for no good reason.
npm install -g svgo cd ckeditor5-package-name/theme/icons svgo --enable removeTitle -i .
SVGO reduces the icon size up to 70%, depending on the software used to create it and the general complexity of the image.