Pretty-printing jsdom objects is way too verbose

[gaearon]

This is what I see with a single failing expectation:

This is because jsdom has its implementation under a Symbol() key, and a single jsdom element brings the whole jsdom with it.

Can we fix it by adding some sort of pretty-printing for jsdom? I know that's what @yaycmyk attempted in jamiebuilds/pretty-format#47 but it received a comment:

I also don't think HTML printing should be a default. I don't actually want to pretty-print HTML elements in Jest like this.

If we really want to do this, the right way is to build a plugin and then use instanceof checks with the objects coming from jsdom.

Shall we do this them?

Another way to fix this specific issue would be to skip Symbol() keys since they're intentionally "private". The downside would be that comparing two objects with different values under Symbol keys would presumably miss those differences. We could maybe only print Symbol() keys if we know the difference is inside of them but skip them otherwise.

Yet another way to fix it would be to limit nesting when printing difference to something like 3. I think it's what Node does in console.log but I might be wrong.

[thymikee]

@yaycmyk are you interested in making such plugin for pretty-format?

[quantizor]

I'm pretty in the weeds on a personal project, so I can't commit the time right now. Someone else can take over my work though!

[thymikee]

Thanks! Marking this as a Good First Task then, since majority of the work is done by you.

[mute]

I'd like to pick this up (assuming it's still valid/desired).

[cpojer]

Go for it! Check out the pretty-format package in the Jest repo and how the plugin system works.

[github-actions]

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