[Feature] ElementHandle.getTagName()

[tjenkinson]

I'd like to retrieve the name of the tag from a playwright.ElementHandle, and it seems like this is not possible at the moment.

Something like

const $parent = await $el.$('xpath=..');
const tagName = await $parent.getTagName(); // <--

[JoelEinbinder]

our ElementHandle extend JSHandle, so you can do

const tagName = await $parent.evaluate(e => e.tagName);
// or
const tagName = await $parent.getProperty('tagName');

[tjenkinson]

@JoelEinbinder thanks. I tried$parent.evaluate but it looks like it runs in the main context not an isolated one? Does $parent.getProperty('tagName') run in its own context?

Thanks

[JoelEinbinder]

All of these run in the main context. You expect the page to fight you on Element.tagName? That seems highly unusual.

Considering we have innerHTML and textContent, I don't see much harm in adding tagName. But I'm curious about why you would need it.

[tjenkinson]

Do the calls like $el.getAttribute() also run on the main context or are these dev tools protocol? I'm still pretty fuzzy on how calls are getting through to the browser and where the work's happening.

I'm trying to trust the pages I'm running on as little as possible.

The particular thing I'm working on right now is trying to build up some bread crumbs from a target element up to the root, so that we can attempt to find it again later. For this I want to keep going up the tree and recording what the tag types are (along with other info like id if they have one and some of their innerText).

[tjenkinson]

It looks like getAttribute() and the other functions you mentioned in "src/server/dom.ts" uses _evaluateInUtility

  async _evaluateInUtility<R, Arg>(pageFunction: js.Func1<[js.JSHandle<InjectedScript>, ElementHandle<T>, Arg], R>, arg: Arg): Promise<R> {
    const utility = await this._context.frame._utilityContext();
    return utility.evaluateInternal(pageFunction, [await utility.injectedScript(), this, arg]);
  }

Is this an isolated context?

I could probably submit a PR to add Element.tagName() if it would follow the same pattern?

[pavelfeldman]

@tjenkinson: I'd stick with parent.evaluate(e => e.tagName) until it bites you? Otherwise we end up mirroring the entire DOM api. I think we were discussing the optional isolated world parameter in the evaluate with you. That's more likely to happen!

[tjenkinson]

Yep that was me (#4377)

I will need the the call to be isolated. Happy to try and open a PR for #4377 if someone could point me in the right direction, otherwise I'll probably end up adding this in a fork because it looks simpler and using that for now.

[pavelfeldman]

Folding into #4377