Transforms are not ran on snapshotSerializers

[Daniel15]

Do you want to request a feature or report a bug?
Bug

What is the current behavior?
Snapshot serializers can be configured in the Jest config as follows:

  "snapshotSerializers": [
    "<rootDir>/FooSerializer.js"
  ]

However, Jest does not appear to run the file through the transform script. This is blocking me from using Flow in my snapshot serializers, as it throws "SyntaxError: Unexpected identifier" when it tries to execute the file (since it's not being transformed)

It looks like isInternalModule is true in transformAndBuildScript so it's not running the transforms.

What is the expected behavior?
Transforms should be ran on these files.

Please provide your exact Jest configuration and mention your Jest, node, yarn/npm version and operating system.
Internal Facebook www

[rogeliog]

Thanks for reporting!
You can try using expect.addSnapshotSerializer() in the mean time

[Daniel15]

Thanks for the suggestion! Could I call addSnapshotSerializer from one of the setupFiles? The issue with adding it in the test itself is that everyone that uses a particular file would need to know to add its serializer. That's why I wanted to configure it in the Jest config 😃

[rogeliog]

I don't think that you can call from the setupFiles... I think that passing it in the config would be the only way

[cpojer]

This is definitely a bug!

[thymikee]

@Daniel15 you can use setupTestFrameworkScriptFile just for that, but I guess you probably already solved that 😄.

[Daniel15]

@thymikee Good idea! The way I worked around this was simply by avoiding any code that needed to be transformed (ie. no Flow typing), but using setupTestFrameworkScriptFile sounds like a better approach. Thanks for the suggestion :)

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