feat: cy.selectFile() (#19332)

[BlueWinds]

• Closes Adding Ability to Submit File to Input Element From Local Filesystem (file upload) #170

User facing changelog

Adds Cypress.Buffer, exposing the Buffer polyfill for working with binary data.

Adds native support for .selectFile(), allowing interaction with file input elements as well as simulating a user drag-dropping files over the document.

cy.get('input[type="file"]').selectFile('cypress/fixtures/myfixture.json');

The API is similar to cypress-file-upload, and we have provided a migration guide for previous users of that plugin.

For full details, see the .selectFile() documentation.

Additional details

The documentation and migration guide contain extensive information about all the options and features of this new command.

PR Tasks

• Have tests been added/updated?
• Has the original issue (or this PR, if no issue exists) been tagged with a release in ZenHub? (user-facing changes only)
• Has a PR for user-facing changes been opened in cypress-documentation? TODO - waiting on cy.selectFile docs cypress-documentation#4241 to merge into unification, will then make a docs PR against master.
• Have API changes been updated in the type definitions?
• [N/A] Have new configuration options been added to the cypress.schema.json?

[cypress-bot]

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[cypress]

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Test summary

19129 • 0 • 218 • 0 • 1

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Run details

Project	cypress
Status	Passed
Commit	5f74fe0
Started	Jan 11, 2022 7:49 PM
Ended	Jan 11, 2022 8:00 PM
Duration	11:28 💡
OS	Linux Debian - 10.10
Browser	Multiple

View run in Cypress Dashboard ➡️

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Flakiness

	cypress/integration/commands/net_stubbing_spec.ts		1
1	network stubbing > waiting and aliasing > can timeout waiting on a single request using "alias.request"

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[BlueWinds]

@cowboy - Added Cypress.Buffer to this branch rather than its own PR, because it was a small change and it also didn't make sense to do separately (I would still have to update this PR as well, to use it in the tests / type docs).

cypress-services PR to add on.cypress link to new docs page: https://github.com/cypress-io/cypress-services/pull/4195

[AtofStryker]

@BlueWinds looks like theres an issue adding the type BufferModule = import("buffer/") to the declaration file. Is that right?

[BlueWinds]

@BlueWinds looks like theres an issue adding the type BufferModule = import("buffer/") to the declaration file. Is that right?

Ah, I thought I'd fixed that. Pushed a new change that should address it for real this time.

[tnrich]

A heads up that the changelog link to the blog about the new functionality is broken:

https://cypress.io/blog/2022/01/18/uploading-files-with-selectfile/

[cypress-bot]

Released in 9.3.0.

This comment thread has been locked. If you are still experiencing this issue after upgrading to
Cypress v9.3.0, please open a new issue.

[BlueWinds]

We released the code late in the evening and didn't publish the blog post until the following day. Fixed now, thanks for the report.