Typescript error when use wrapper.classes().includes

[Yawenina]

Version

1.0.0-beta.16

Reproduction link

https://github.com/Yawenina/vue-test-utils-classes

Steps to reproduce

npm install

npm run serve

What is expected?

no error

What is actually happening?

In my test file, I write a test like this:

expect(wrapper.classes().includes('a')).toBe(false);

but when I ran npm run serve, typescript yield an error:

ERROR in vue-test-utils-classes/tests/unit/HelloWorld.spec.ts
10:30 Property 'includes' does not exist on type 'void | string[]'.
  Property 'includes' does not exist on type 'void'.
     8 |       propsData: { msg },
     9 |     });
  > 10 |     expect(wrapper.classes().includes('a')).toBe(false);
       |                              ^
    11 |   });
    12 | });
    13 |
Version: typescript 2.9.1

---

I read the source code and find the type definition of the classes() method is this:

classes(): Array<string> | void

Maybe because the return value could be void so it does not have a includes method.

When I change it to :

classes(): Array<string>

the error disappears and everything works ok.

[eddyerburgh]

Actually it never returns void, so the definition file is incorrect. Would you like to make a PR that removes the void? There are two definition files that need to be changed, one in packages/test-utils/ and one in packages/server-test-utils

[Yawenina]

Sure, I'd love to.

[Yawenina]

I didn't find classes definition in packages/server-test-utils, so I only changed it in packages/test-utils/.

PR #685 solves this issue.

[eddyerburgh]

Ah sorry I forgot that we don't have Wrappers in server-test-utils 😅

Thanks for the PR 👍