Custom transformer for compiling Embedded Ruby template files (.erb) for use in the Jest JavaScript testing framework.
Add to project using your package manager, e.g. yarn:
yarn add jest-erb-transformer --devEnsure the "erb" file extension and the jest-erb-transformer extension matcher and configuration is included in the project's package.json jest key:
"moduleFileExtensions": [
"js",
"erb"
],"transform": {
"^.+\\.erb$": "jest-erb-transformer"
}See the Jest docs for more information on the configuration of transformers.
To add custom configuration, such as using the Ruby on Rails runner for ERB compilation, add a configuration object to the transformer entry in the project package.json using the Jest transformer configuration syntax. For example, to compile in the rails environment:
"transform": {
"^.+\\.erb$": [ "jest-erb-transformer", { "application": "rails" } ]
}By default the transformer does not process its output with Babel.
To perform post-processing with Babel, either configure the transformer babelConfig option as outlined in the options table below, or I have found including the .erb files in the babel-jest transformer directly has worked in some scenarios. For example:
"transform": {
"^.+\\.js(?:\\.erb)?$": "babel-jest",
"^.+\\.erb$": [ "jest-erb-transformer", { "application": "rails" } ]
}| Key | Default Value | Description |
|---|---|---|
"application" |
"ruby" |
Transformer is run using ruby by default, set value to "rails" to use bin/rails runner. The "rails" option can be useful if the .erb files include Ruby on Rails specific environment variables such as Rails.application.credentials. |
"engine" |
"erb" |
Transformer uses the ruby 'ERB' engine by default, to use the Erubi engine set the value to "erubi". |
"timeout" |
"5000" |
Set the timeout duration in milliseconds for the compilation of individual files. |
"babelConfig" |
false |
Process the output of the ERB transformer using babel-jest. Options:
|
Feel free to ask questions using issues or contribute if you have any improvements.
MIT