refactor(events): Introduce and use event type predicates #8538
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Introduce predicates for testing Abstract event subclasses based on their .type properties. These are useful because there are places where it is not possible to use instanceof <ClassConstructor> tests for type narrowing due to load ordering issues that would be caused by the need to import (rather than just import type) the class constructors in question.
Simplify several sections of code by using type predicates for type narrowing and thereby avoiding the need for explicit casts.
cpcallen
force-pushed
the
refactor/event-type-predicates
branch
from
0f6ac10
to
0b60195
Compare
rachel-fenichel
approved these changes
Aug 20, 2024
Yeah: since I set up auto-sorting of imports, and this by default removes unused imports, any remaining unused imports now trigger both lint and format failures. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The basics
The details
Proposed Changes
Introduce predicates for testing
Abstractevent subclasses based on their.typeproperties. These are useful because there are places where it is not possible to useinstanceof <ClassConstructor>tests for type narrowing due to load ordering issues that would be caused by the need toimport(rather than justimport type) the classconstructors in question.
Simplify several sections of code by using these type predicates for type narrowing, and thereby avoiding the need for explicit casts.
Reason for Changes
Cleanup and preparation for fixing #8225 et al.
Test Coverage
npm test.Additional Information
The type predicates are not currently reexported from
core/blockly.ts. This could be done by adding suitableexport … from …statements tocore/events/events.ts, but I've opted not to do this until there is a good reason to: in most cases it is probably preferable that code usee instanceof EventClassrather thanisEventClass(e), since the former is a stricter and less easily subverted type check, and code outside ofcore/can always access the event constructors without any cyclicimportissues.