Dom-testing-library: Screen Export: Should it include the debug method?

[jkdowdle]

Describe the feature you'd like:

I was just trying out the screen object to power the queries of my tests and the first thing I did was try using the debug method, expecting it to be there like from the object you get back from render in
'@testing-library/react'.

import React from 'react'
import { screen } from '@testing-library/react'

test('works', () => {
    setup()

    screen.debug()
})

And I noticed that it was not available. I would love to submit a PR to add it, but before I went looking around on how to do that I thought I would double check and make sure that that was not a conscious decision to leave out. Maybe some constraints on the difficulty of adding it or something like that.

Suggested implementation:

Describe alternatives you've considered:

We can continue getting the debug method off the returned object from rendering.

Or, as was mentioned bellow, use the logDOM export.

import {logDOM} from '@testing-library/react'

logDOM() // logs out document.body

Teachability, Documentation, Adoption, Migration Strategy:

This would increase the surface area by a little bit, but since screen was already added, it would not be that much more to add. I think users, like myself, would expect it to be there.

I want to thank all the maintainers, keep up the great work!

[kentcdodds]

Hi @jkdowdle,

It's already supported:

import {logDOM} from '@testing-library/react'

logDOM() // logs out document.body

Though I can see the value of having it on screen so you can call/remove it without having to update imports.

Thoughts from anyone else?

[balazsorban44]

I did not think of it before, but now I am sure I would unconsciously go and try to get debug from screen every time! :sweat_smile:

[kentcdodds]

I'm not opposed to adding it, but I'd like to hear arguments for/against.

[alexkrolick]

Enzyme has a debug method for nodes, might make it easier to migrate nog screen did too

[benmonro]

I vote Yes as this would make it a lot easier to report on debug in the testing lint rule. Actually for that matter why not Make it a top level export? I'd even support a breaking change to remove it from the results as that makes it quite tricky to lint when used with Custom render functions.

For note, the goal of the no debug lint rule is to keep it out of CI, and only use it locally temporarily when Debugging

[jkdowdle]

@benmonro That sounds like the best argument so far for only allowing the top level export for the debug method, if I understood correctly. I personally haven't used the eslint rules yet for @testing-library but I'd like to start. Thank you

[benmonro]

@jkdowdle there's also the jest-Dom lint plugin that I wrote. 😎

[ilovett]

I assumed based on experience with debug method returned from render that I could either do screen.debug or perhaps debug(screen) -- perhaps logDOM just needs to be better documented here https://testing-library.com/docs/dom-testing-library/api-helpers#debugging

Personally I like the syntax of debug(screen) ^_^ or debug(container) and I think it would maintain a consistent API

import { debug } from "@testing-library"

render();
debug(screen);

[kentcdodds]

The benefit of putting it on screen rather than just having an extra export is that you don't have to update the imports to use debug. You can just type screen.debug() and then you can delete it and not worry about imports.

I think I'm in favor of this. Anyone wanna PR it?

[jkdowdle]

@kentcdodds I would agree! and I'd love to try to do the PR

[kentcdodds]

Go for it 👍

[jkdowdle]

debug has been added to the the screen object.
https://github.com/testing-library/dom-testing-library/pull/429 and released in 6.11.1 6.12.0 as noted below in @bencomeau's comment

[bencomeau]

debug has been added to the the screen object.

429 and released in 6.11.1 https://github.com/testing-library/dom-testing-library/releases/tag/v6.11.1

Great job on this! Just noting to clarify for future readers that it seems it was released with v6.12.0. Thanks again for the work to implement!