TypeError: Cannot read property 'startsWith' of undefined at Coverage.hasNoOutput

[alireza-salemian]

Hi
I get 'TypeError: Cannot read property 'startsWith' of undefined at Coverage.hasNoOutput' after run karma test.
a complete log attached for more details.
log.txt

[simonvizzini]

I have the same issue. Have you found a solution or workaround yet?

[simonvizzini]

I got rid of this error by setting instrumentation to false:

karmaTypescriptConfig: {
  tsconfig: "./tsconfig.json",
  coverageOptions: {
    instrumentation: false
  }
}

But no tests execute, Chrome opens an empty page, with just a green header: Karma v4.4.1 - connected. The CLI outputs the following:

Chrome 78.0.3904 (Linux 0.0.0): Executed 0 of 0 SUCCESS (0.001 secs / 0 secs)

I tried to add the mime option to my karma.conf.js file as suggested in a couple StackOverflow answers:

mime: {
    'text/x-typescript': ['ts','tsx']
}

but no luck.

[vidartf]

I also have this problem. An initial investigation by stepping through the code reveals that this occurs when the typescript compile-host for some reason do not call the writeFile callback for any of the files. The compilation is otherwise marked as a success ("Compiled 164 files in X ms`). I'll keep investigating to see if I can figure out what causes this to happen.

[vidartf]

Hm. For me it got fixed by setting noEmitOnError: false, even though I don't get any errors reported. Note that I do need to use skipLibCheck: true in my project in order to avoid some upstream typing issues (no idea if related), but I am still normally able to emit code when this flag is set.

Hopefully this can help someone else either work around the issue, or figure out the root problem :)

[tva-TIS]

Do you have any exlusions set within coverageOptions? I get the error too, but only if I use the exlude option.

[tva-TIS]

So I just realized I forgot to exclude the d.ts files. This would explain why the outputText is undefined (d.ts files dont result in any js being compiled), so I guess that you are feeding empty files to istanbul too.

[guoyunhe]

I have the same error. Hope someone can fix it.

[cefn]

Has karma-typescript been broken in this way for 2 years without any resolution?

I hit the same dead end after starting up a brand new repo with just one React component and trying to follow the basics of using karma-jasmine karma-typescript jasmine-enzyme and battled with it for hours in various ways - never functioned to load and run my single React component test and was always running 0 of 0 tests.

As a workaround I started with https://github.com/medington/jasmine-enzyme-ts (thanks @medington) which was a proof-of-concept repro of a working Jasmine+Enzyme+Karma test suite. Unfortunately things have moved on since then and it doesn't work out of the box - unpinned packages at their latest versions break it.

However, I fixed it up so that the Enzyme tests pass by updating it to all the latest packages, and tweaking here and there. You can see the changes at cefn/jasmine-enzyme-ts@9003027

At the time of writing the repo at https://github.com/cefn/jasmine-enzyme-ts now runs two Enzyme tests written in Typescript correctly using Jasmine tests in a Chrome Karma instance without hitting the errors described in this issue. It uses a webpack configuration to transform the typescript rather than the prior approach I attempted based on karma-typescript which was broken.

For CI and hopefully later reproduction for others I have committed pnpm-lock.yaml so installing the project with pnpm install --frozen-lockfile shouldn't be susceptible to packages which update and break it.

[timvahlbrock]

Has karma-typescript been broken in this way for 2 years without any resolution?

I hit the same dead end after starting up a brand new repo with just one React component and trying to follow the basics of using karma-jasmine karma-typescript jasmine-enzyme and battled with it for hours in various ways - never functioned to load and run my single React component test and was always running 0 of 0 tests.

As a workaround I started with https://github.com/medington/jasmine-enzyme-ts (thanks @medington) which was a proof-of-concept repro of a working Jasmine+Enzyme+Karma test suite. Unfortunately things have moved on since then and it doesn't work out of the box - unpinned packages at their latest versions break it.

However, I fixed it up so that the Enzyme tests pass by updating it to all the latest packages, and tweaking here and there. You can see the changes at cefn/jasmine-enzyme-ts@9003027

At the time of writing the repo at https://github.com/cefn/jasmine-enzyme-ts now runs two Enzyme tests written in Typescript correctly using Jasmine tests in a Chrome Karma instance without hitting the errors described in this issue. It uses a webpack configuration to transform the typescript rather than the prior approach I attempted based on karma-typescript which was broken.

For CI and hopefully later reproduction for others I have committed pnpm-lock.yaml so installing the project with pnpm install --frozen-lockfile shouldn't be susceptible to packages which update and break it.

@cefn

I've left a little investigation report in #480, which again confirmed, that this is an error message that does not contain enough information. The report also contains a little info on how to set a fitting debugging point, which files the output cannot be found for.

[D4nte]

I was able to fix that by ensuring that I use a tsconfig file with:

  "compilerOptions": {
    "noEmit": false
  },

Now I am getting a Uncaught Error: Can't find ... error that I am investigating

[moughxyz]

Issue for me was emitDeclarationOnly was set to true in tsconfig. Should be false.