Jest setup “SyntaxError: Unexpected token export”

Question

I\'m implementing tests into an existing project that currently has no tests. My tests are failing to compile node_modules/ imports.

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Answer 1

Posting a more complete answer here:

Jest by default does not transform node_modules because node_modules is huge. Most node modules are packaged to expose ES5 code because this is runnable without any further transformation (and largely backwards compatible).

In your case, lodash-es specifically exposes ES modules, which will need to be built by Jest via babel.

You can try narrowing your whitelist down so Jest doesn't try to pass every javascript file within node_modules through babel.

I think the correct configuration in your case is:

"jest": {
  "transformIgnorePatterns": [
    "/!node_modules\\/lodash-es/"
  ]
}