TypeError: Jest: a transform's process function must return a string,

[ghost]

I'm submitting a ... (check one with "x")

[ ] bug report => search github for a similar issue or PR before submitting
[ ] feature request
[x] support request

Current behavior

Fails with that errors:

$ npm test

> [email protected] test /home/r/w/webpack-test2
> jest

Failed to compile src with `tsc` at `vue-preprocessor`
 FAIL  tests/add.test.ts
  ● Test suite failed to run

    TypeError: Jest: a transform's `process` function must return a string, or an object with `code` key containing this string.
      
      at ScriptTransformer.transformSource (node_modules/jest-runtime/build/script_transformer.js:227:15)
      at Object.<anonymous> (tests/add.test.ts:6:15)

  console.info node_modules/vue/dist/vue.common.js:8248
    You are running Vue in development mode.
    Make sure to turn on production mode when deploying for production.
    See more tips at https://vuejs.org/guide/deployment.html

Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        1.509s
Ran all test suites.
npm ERR! Test failed.  See above for more details.

Expected behavior

Mormal completion of tests

Minimal reproduction of the problem with instructions
Minimal example here may be big) so I created minimal test example project.
Project contains vue app, and 2 type of tests. Testing .ts files and .vue componet.

https://gitlab.com/rokkerruslan/jest-ts-vue-test

What is the motivation / use case for changing the behavior?

I need testing as simple ts files and vue components files.

Please tell us about your environment:

npm 5.5.1

• jest-vue-preprocessor: 1.1.X

1.3.1

• Node version : [ OSX | Linux | Windows ]
  v9.0.0

• Platform: [ OSX | Linux | Windows ]
  Linux rpc 4.10.0-37-generic mapCoverage:true produces misleading Line in coverage report (wrong sourcemaps) #41~16.04.1-Ubuntu SMP Fri Oct 6 22:42:59 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

Thanks for any asnwers!

[khanharis87]

@rokkerruslan did you solve this issue?

[Michael-Gungaram]

Any solution about this? Having the same issue.

[RehanSaeed]

Same here, any solutions?

[jeroenschieven]

@khanharis87 @Michael-Gungaram @RehanSaeed Not sure if still relevant for you guys, but maybe it is for everyone else having this issue.

I had the same problem. Turned out that the problem only occurred when using Object spread syntax. The object spread syntax isn't supported by babel-core, so I had to install a plugin for that and add it to my .babelrc file. Check https://babeljs.io/docs/plugins/transform-object-rest-spread for more information about the plugin.

The problem could also occur with any other es7/es[future-releases] syntax your using in your files which is not supported by babel-core.

[samuelterra22]

thx @jeroenschieven ! I was having the same problem.

[Prior99]

I am experiencing the same problem while using Typescript. Any solutions?

[MiguelSi6]

i had to add "jest-junit": "13.0.0", to package.json and the problem went away