[Feature] Compatibility with shadow dom

[stefanbratosin]

Current behavior:

Can this plug-in work with shadow dom as well ?
When I tried to use it with our application I got an exception the element is detached from dom.
It would be really nice if this plug-in can work with shadow-dom.

Desired behavior:

This plug-in works with shadow-dom. If it is working with shadow-dom if an example could be added to the read-me page would be really helpful.

Versions

[abramenal]

Hi @stefanbrato
Thanks for the feedback!

Well, that's actually a nice one.
Can you please share any small snippet of your component implementation + tests as well as exception you get in order to get more context?
I think it might be quite easy one, but need to figure out what is not yet supported (hopefully not the event triggering).

[stefanbratosin]

Hello @abramenal ,

Here is a small snippet of the command added in support/commands.js:

Cypress.Commands.add("uploadFile", (fileName) => {
    cy.fixture(fileName).then(fileContent => {
        cy.get("other-app")
            .shadowGet("other-app-adp")
            .shadowGet("other-app-adp-file-add-modal")
            .shadowGet("div.drop-zone")
            .upload(
                    { fileContent, fileName, mimeType: 'application/json' },
                    { subjectType: 'drag-n-drop'},
                );
      });
});

Here is an example of the simple test we had for this upload feature:

it.only("should add a new file", () => {
            cy.uploadFile("example.json");
        })

And here is the exception we receive:

Error:       CypressError: cy.upload() failed because this element is detached from the DOM.

<div class="drop-zone">...</div>

Cypress requires elements be attached in the DOM to interact with them.

The previous command that ran was:

  > cy.shadowGet()

This DOM element likely became detached somewhere between the previous and current command.

Common situations why this happens:
  - Your JS framework re-rendered asynchronously
  - Your app code reacted to an event firing and removed the element

You typically need to re-query for the element or add 'guards' which delay Cypress from running new commands.

https://on.cypress.io/element-has-detached-from-dom

• Also we are using the shadow commands plugin from https://gist.github.com/egucciar/5f31c84f19190b5e64737a9d80eb7a9d

Regarding the snippet of the component code, we are working for a internal project closed source. We are working on a poc for this component and we will send it to you.

Please let me know if I can help you with more information.

[abramenal]

@stefanbrato I see the case now.
You're using functionality extension for shadow DOM support (that is not yet supported originally).
I see we need to introduce a new command like shadowUpload that will work on top of this package.

Prior to that I've created another package – https://github.com/abramenal/cypress-shadow-dom.
Hopefully will finish the implementation really soon – feel free to contribute 😈

After that, on top of shadow DOM package will make shadowUpload command inside cypress-file-upload thing.

Feel this coming in a week or so.. will let u know.

[abramenal]

@stefanbrato realized that's not a quite easy one to do 😈
Feel free to join testing & designing that package properly:
https://github.com/abramenal/cypress-shadow-dom

[stefanbratosin]

Hello @abramenal , indeed it seems it is a bit out of my league to do this modification, but we did find a workaround and I though it would be nice to share it, until the plugin is updated:

uploadFile(filename, fixturePath = 'swaggers/'){
        const button = this.uploadFileInput();
        const fixture = fixturePath + filename; 
        const type = 'application/json';

        button.then(subject =>
            cy.window().then(win =>
                cy.fixture(fixture, 'base64')
                .then((json) => {
                const el = subject[0];
                const blob = new Blob([JSON.stringify(json, null, 2)], {type : 'application/json'});
                const testFile = new win.File([blob], filename, { type });
                const dataTransfer = new win.DataTransfer();
                dataTransfer.items.add(testFile);
                el.files = dataTransfer.files;
                el.dispatchEvent(new CustomEvent('change'));
            })));
    }

[abramenal]

@stefanbrato that's a great finding!
It seems there's no need to spend effort on supporting shadow DOM but rather adjust the configuration inside to let cypress omit elements validation.
I will check that later today, anyways let you know if I found a way to.

[abramenal]

Implementation is done, need some time for proper testing – release for this improvement is coming.

[abramenal]

@stefanbrato

so now you can use the command for shadow dom components as well:

const fileName = 'data.json';

cy.fixture(fileName).then(fileContent => {
  yourWrappedShadowSubject.upload(
    { fileContent, fileName, mimeType: 'application/json' },
    { subjectNature: 'shadow', subjectType: 'drag-n-drop' },
  );
});

If you're using https://github.com/abramenal/cypress-shadow-dom
it's likely will look like:

const fileName = 'data.json';

cy.fixture(fileName).then(fileContent => {
  cy.document()
  .shadowGet('my-shadowed-form my-shadowed-dropzone')
  .upload(
    { fileContent, fileName, mimeType: 'application/json' },
    { subjectNature: 'shadow', subjectType: 'drag-n-drop' },
  );
});

[abramenal]

I am also working on reference solutions (aka recipes) to demonstrate what we can do with the plugin: #80

[abramenal]

@stefanbrato
Much thanks to you!
That was a great code snippet which helped to understand how to tweak the plugin.
I've added you to our honored contributors list 😈 😈 😈

[abramenal]

I've added a separate recipe to demonstrate this specific case:
https://github.com/abramenal/cypress-file-upload/tree/master/recipes/shadow-dom-native