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Webpack Canary

Run dependency examples against webpack versions to detect incompatibilities.


npm install --save-dev webpack-canary
# or 
yarn add --dev webpack-canary

Once installed it will provide two binaries canary and squawk. Canary can be installed globally but it's best to install it on a project level.

Another way of using the Canary is by pulling down this repo and running the code from it, treating it as a general Webpack testbed.



Expected usage of the canary is to check multiple versions of webpack against a set of dependencies and squawk if there are any failures. The squawk task is a runner to just that. Webpack and dependency versions should stored in webpack-canary.conf.js in your project root folder. Check out the example for the config format.

Use npm run squawk to run all dependencies against all versions of webpack, and generate a report with successes and failures. This command supports only one flag: --verbose.

The squawk command can receive all the CLI options listed bellow, but they also can be set in the config (but with camelCase instead of kebab-case). The config has the priority before CLI arguments if both are set.

For loaders and plugins

If a loader or plugin is the tool user, it will most likely define all webpack versions it wants to support with the current dependency version.

For example, if a loader foo-loader wants to support webpack ^2.3.0 it should set the wanted Webpack versions to 2.3, 3, and webpack/webpack#master to check the latest version.

For webpack

If Webpack is the tool user, it will most likely define the latest webpack version and a list of dependencies and their versions.

npm ignore

If you have npm ignore defined, it will most likely skip the download of tests and examples. Therefore, you may need to use tarballs for dependencies instead of regular npm versions: instead of webpack-dev-server@2.3.0. Keep in mind that the 2.3.0 version in the url is defined with the git tag, not with the npm release!

CLI Interface

To run a specific dependency version against a specific version of webpack, use the canary CLI interface.

canary --webpack=<webpack_reference> --dependency=<dependency_reference>
  • --webpack can be a version or path to remote repository
  • --dependency can be a dependency name (with or without version) or path to remote repository
  • --package-manager (optional) can be set to yarn to use yarn for installation of modules. If not set (or set to anything else) it will default to npm
  • --test A command that will run dependency tests
  • --test-path A temporary path where the dependency will be copied and the tests will be run. Important when jest is used as test runner as it will ignore all paths that have node_modules in them. The default path is <webpack-canary>/test_modules/test-dependency
  • --example-dir can be one or more relative paths to examples folders (e.g. --example-dir ./demo or --example-dir demo). If not set, examples check will be skipped.
  • --progress Show the progress bar (it will override the loglevel option and set it to warn)
  • --timeout Interrupts command execution after the defined time (default is 60s). Applies to installing dependencies and running tests.


# Published versions in registry
canary --webpack=2.2 --dependency=raw-loader

# Development versions in remote repositories
canary --webpack=webpack/webpack#master --dependency=


If you want to check examples, the dependency should include an directory (defined in the example-dir option) which contains an example setup with corresponding webpack config (ie. must have a webpack.config.js file). This config is run with the installed webpack version to confirm compatibility. If a custom command needs to be run, there should be an accompanying file which contains the command in a codeblock.

Readme file

The readme can also contain any other content that would usually be in the file. If there are multiple code blocks, only the first one will be used.

# A title

Some content

```npm run example```

Some other content

```command that will be ignored```

The command can also contain some placeholders. Right now, only <insert local ip> is supported (will be replaced with


Alistair Brown

Darko Kukovec

Andrei Zvonimir Crnkovic

Sean Larkin

Joshua Wiens