Compile Lightning web components for Jest tests.
Jest transformers modify source files in preparation for tests based on regular expressions. See Jest docs for more information.
The transformer modules in this package allow LWC developers to test components that reference @salesforce modules by transforming those import statements into assignment statements that work outside of a Salesforce application container.
yarn add -D @lwc/jest-transformer
Update your jest config to point the transformer to this package:
{
"jest": {
"moduleFileExtensions": ["js", "html"],
"transform": {
"^.+\\.(js|html|css)$": "@lwc/jest-transformer"
}
}
}