add info about ErrorWrapper object

[iztsv]

What problem does this feature solve?

As I can see find method returns Wrapper object if element found or ErrorWrapper object if not element found. Both are implement BaseWrapper.

I think it will be good to add this information in order to do more clear info about returning type of find.

Also, may be create page for ErrorWrapper object.

What does the proposed API look like?

Returns: {Wrapper}

to something like

Returns: {Wrapper | ErrorWrapper}

...some notes when ErrorWrapper returned and example...

[eddyerburgh]

I'm not sure there's value in telling users about the error wrapper. It's purpose is to handle cases when an element isn't found, and it has the same methods as the Wrapper.

What notes about the ErrorWrapper would you find useful?

[iztsv]

@eddyerburgh thanks for the reply.

Maybe enough to add something like this notes for find method:

> Example: ...

Note: you can check that at least one element is found using `exists` method:

const div = wrapper.find('div')
expect(wrapper.exists()).toBe(true)

Because I expect that expect(wrapper.find('div')).toBe(false) if no one element is found, but it's always will be true - maybe it's my strange logic 😄

[eddyerburgh]

That's a reasonable assumption, but the docs do say find returns a Wrapper object. I don't think we need to add more detail than that.

[iztsv]

Thanks!

[nidkil]

Hi guys, sorry to comment on a closed issue, but I have just run into the same issue. Calling find returns ErrorWrapper instead of the expected false. I needed to Google around to findout why. What is the harm of clarifying this in the documentation? It is not obvious that it can be queried with .exists. A short explanation explaining that if find does not find a match it returns an ErrorWrapper that can be checked with .exists?

[eddyerburgh]

Ok, we could add a sentence in the find docs. Would you like to write it @nidkil ?

[tomasbjerre]

I prefer naming methods like:

• find(x) that will search for x. It may not find anything, and it is totally expected.
• get(x) that will get x. It will always return value of x or it will throw exception stating that x could not be found.

So I am missing the get method here.

See #1298

[scridget]

Agreee - running into this as well. exists returns true, even when the actual component isn't found.

[Robin-Hoodie]

Testing this with @vue/test-utils@1.0.3 and exists() actually returns false for an ErrorWrapper component

This can also be found in the sourcecode:

vue-test-utils/packages/test-utils/src/error-wrapper.js

Line 74 in 4b0c5c9

exists(): boolean {