d0ad9343f0
## The basics - [x] I [validated my changes](https://developers.google.com/blockly/guides/contribute/core#making_and_verifying_a_change) ## The details ### Resolves Fixes part of #8207 Fixes part of #3370 ### Proposed Changes This introduces initial broad ARIA integration in order to enable at least basic screen reader support when using keyboard navigation. Largely this involves introducing ARIA roles and labels in a bunch of places, sometimes done in a way to override normal built-in behaviors of the accessibility node tree in order to get a richer first-class output for Blockly (such as for blocks and workspaces). ### Reason for Changes ARIA is the fundamental basis for configuring how focusable nodes in Blockly are represented to the user when using a screen reader. As such, all focusable nodes requires labels and roles in order to correctly communicate their contexts. The specific approach taken in this PR is to simply add labels and roles to all nodes where obvious with some extra work done for `WorkspaceSvg` and `BlockSvg` in order to represent blocks as a tree (since that seems to be the best fitting ARIA role per those available: https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Reference/Roles). The custom work specifically for blocks includes: - Overriding the role description to be 'block' rather than 'tree item' (which is the default). - Overriding the position, level, and number of sibling counts since those are normally determined based on the DOM tree and blocks are not laid out in the tree the same way they are visually or logically (so these computations were incorrect). This is also the reason for a bunch of extra computation logic being introduced. One note on some of the labels being nonsensical (e.g. 'DoNotOverride?'): this was done intentionally to try and ensure _all_ focusable nodes (that can be focused) have labels, even when the specifics of what that label should be aren't yet clear. More components had these temporary labels until testing revealed how exactly they would behave from a screen reader perspective (at which point their roles and labels were updated as needed). The temporary labels act as an indicator when navigating through the UI, and some of the nodes can't easily be reached (for reasons) and thus may never actually need a label. More work is needed in understanding both what components need labels and what those labels should be, but that will be done beyond this PR. ### Test Coverage No tests are added to this as it's experimental and not a final implementation. The keyboard navigation tests are failing due to a visibility expansion of `connectionCandidate` in `BlockDragStrategy`. There's no way to avoid this breakage, unfortunately. Instead, this PR will be merged and then https://github.com/google/blockly-keyboard-experimentation/pull/684 will be finalized and merged to fix it. There's some additional work that will happen both in that branch and in a later PR in core Blockly to integrate the two experimentation branches as part of #9283 so that CI passes correctly for both branches. ### Documentation No documentation is needed at this time. ### Additional Information This work is experimental and is meant to serve two purposes: - Provide a foundation for testing and iterating the core screen reader experience in Blockly. - Provide a reference point for designing a long-term solution that accounts for all requirements collected during user testing. This code should never be merged into `develop` as it stands. Instead, it will be redesigned with maintainability, testing, and correctness in mind at a future date (see https://github.com/google/blockly-keyboard-experimentation/discussions/673).
Blockly
Google's Blockly is a library that adds a visual code editor to web and mobile apps. The Blockly editor uses interlocking, graphical blocks to represent code concepts like variables, logical expressions, loops, and more. It allows users to apply programming principles without having to worry about syntax or the intimidation of a blinking cursor on the command line. All code is free and open source.
Getting Started with Blockly
Blockly has many resources for learning how to use the library. Start at our Google Developers Site to read the documentation on how to get started, configure Blockly, and integrate it into your application. The developers site also contains links to:
Help us focus our development efforts by telling us what you are doing with Blockly. The questionnaire only takes a few minutes and will help us better support the Blockly community.
Installing Blockly
Blockly is available on npm.
npm install blockly
For more information on installing and using Blockly, see the Getting Started article.
Getting Help
- Report a bug or file a feature request on GitHub
- Ask a question, or search others' questions, on our developer forum. You can also drop by to say hello and show us your prototypes; collectively we have a lot of experience and can offer hints which will save you time. We actively monitor the forums and typically respond to questions within 2 working days.
blockly-samples
We have a number of resources such as example code, demos, and plugins in another repository called blockly-samples. A plugin is a self-contained piece of code that adds functionality to Blockly. Plugins can add fields, define themes, create renderers, and much more. For more information, see the Plugins documentation.
Contributing to Blockly
Want to make Blockly better? We welcome contributions to Blockly in the form of pull requests, bug reports, documentation, answers on the forum, and more! Check out our Contributing Guidelines for more information. You might also want to look for issues tagged "Help Wanted" which are issues we think would be great for external contributors to help with.
Releases
We release by pushing the latest code to the master branch, followed by updating the npm package, our docs, and demo pages. If there are breaking bugs, such as a crash when performing a standard action or a rendering issue that makes Blockly unusable, we will cherry-pick fixes to master between releases to fix them. The releases page has a list of all releases.
We use semantic versioning. Releases that have breaking changes or are otherwise not backwards compatible will have a new major version. Patch versions are reserved for bug-fix patches between scheduled releases.
We now have a beta release on npm. If you'd like to test the upcoming release, or try out a not-yet-released new API, you can use the beta channel with:
npm install blockly@beta
As it is a beta channel, it may be less stable, and the APIs there are subject to change.
Branches
There are two main branches for Blockly.
master - This is the (mostly) stable current release of Blockly.
develop - This is where most of our work happens. Pull requests should always be made against develop. This branch will generally be usable, but may be less stable than the master branch. Once something is in develop we expect it to merge to master in the next release.
other branches: - Larger changes may have their own branches until they are good enough for people to try out. These will be developed separately until we think they are almost ready for release. These branches typically get merged into develop immediately after a release to allow extra time for testing.
New APIs
Once a new API is merged into master it is considered beta until the following release. We generally try to avoid changing an API after it has been merged to master, but sometimes we need to make changes after seeing how an API is used. If an API has been around for at least two releases we'll do our best to avoid breaking it.
Unreleased APIs may change radically. Anything that is in develop but not master is subject to change without warning.
Issues and Milestones
We typically triage all bugs within 1 week, which includes adding any appropriate labels and assigning it to a milestone. Please keep in mind, we are a small team so even feature requests that everyone agrees on may not be prioritized.
Good to Know
- Cross-browser Testing Platform and Open Source <3 Provided by Sauce Labs
- We test browsers using BrowserStack