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TypeError: Jest: a transform must export something.

See original GitHub issue

Getting an error when trying to use esbuild-runner with the latest version of Jest. Config is simple:

transform: {
    '\\.ts$': 'esbuild-runner/jest',
  },

Versions: jest: 27.0.4 esbuild-runner: 2.2.0

Issue Analytics

State:
Created 2 years ago
Reactions:4
Comments:5 (1 by maintainers)

Top GitHub Comments

4reactions

esturckecommented, Jun 15, 2021

I just ran into this in a new project as well. I was able work around this by creating an ./esr-jest.js:

const { process } = require("esbuild-runner/jest")
module.exports = { process }

And then in ./jest.config.js:

  transform: {
    "^.+\\.tsx?$": "./esr-jest",
  },

I’m not sure why this works, but I’m guessing something to do with how Jest’s requireOrImportModule works.

2reactions

folkecommented, Aug 30, 2021

I just released an update that fixes this

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