To facilitate ES transition, we built some hybrid modules (node-find-up
for example):
* package.json#exports#require exposes old & new API
* package.json#exports#import exposes new API
The reported error shows Jest resolver behavior:
> FAIL test/cjs.test.js
> ● Test suite failed to run
>
> TypeError: findUp.sync is not a function
>
> 11 |
> 12 | module.exports.sync = cwd => {
> > 13 | const filePath = findUp.sync('package.json', {cwd});
> | ^
> 14 | return filePath && path.dirname(filePath);
> 15 | };
> 16 |
Jest does not use Node.js resolver but jest-resolver instead. Here,
jest-resolver uses find-up/index.js instead of find-up/index.cjs and
then does not find old API functions.
Here is a workaround:
* patch package.json to add: "jest": {"resolver":"debian/resolver.js"},
* write the resolver:
$ cat > debian/resolver.js << EOF
module.exports = (request, options) => {
// use defaultResolver
return options.defaultResolver(request, {
...options,
// use packageFilter to modify `package.json` before resolution
// (see https://www.npmjs.com/package/resolve#resolveid-opts-cb)
packageFilter: (pkg) => {
let main = pkg.exports && pkg.exports.require ?
pkg.exports.require : pkg.main;
return {
...pkg,
// change `main` value
main: main
};
},
});
};
EOF