Support conditional type and infer type in Flow #14573
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tests/format/flow/conditional-types/__snapshots__/jsfmt.spec.js.snap
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| @@ -152,7 +152,11 @@ function printTypeParameter(path, options, print) { | |||
| parts.push(name); | |||
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| if (node.bound) { | |||
| parts.push(printTypeAnnotationProperty(path, print, "bound")); | |||
| if (node.usesExtendsBound) { | |||
| parts.push(" extends ", print(["bound", "typeAnnotation"])); | |||
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node.bound is skipped, better not to do that, there could be comments, cursors.
This won't work?
parts.push(" extends ", print("bound"));There was a problem hiding this comment.
Ah, I understand the problem, we should still use printTypeAnnotationProperty. I'll fix it and add comments to explain why it's needed and how it works on monday.
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Found a case
Prettier pr-14573
Playground link
--parser flowInput:
type A = () => infer R extends/* comment */ stringOutput:
Error: Comment "comment" was not printed. Please report this error!
at dn (https://deploy-preview-14573--prettier.netlify.app/lib/standalone.js:29:5817)
at Ze (https://deploy-preview-14573--prettier.netlify.app/lib/standalone.js:29:7308)
at async kn (https://deploy-preview-14573--prettier.netlify.app/lib/standalone.js:29:11045)
at async ju (https://deploy-preview-14573--prettier.netlify.app/lib/standalone.js:34:581)
at async formatCode (https://deploy-preview-14573--prettier.netlify.app/worker.js:159:12)
at async handleFormatMessage (https://deploy-preview-14573--prettier.netlify.app/worker.js:83:24)
at async self.onmessage (https://deploy-preview-14573--prettier.netlify.app/worker.js:38:14)
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| if (key === "checkType" && parent.type === "ConditionalTypeAnnotation") { | ||
| return true; | ||
| } |
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Loos like we are missing cases, it's bad we are not sharing logic between TS and Flow.
Maybe better extract some code first to reuse?
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I fixed the logic and pass the test. I'm not sure how to better extract the code, since there are very little code sharing currently in the file.
My personal opinion is that the existing fallthrough logic for TS nodes already made it harder to understand, and I actually like the more explicit logic among those Flow nodes that don't use fallthrough...
Co-authored-by: fisker <lionkay@gmail.com>
Description
This PR adds support for printing conditional types and the companion infer type using
flow-parser. It uses the existing printTernary helper function that's already implemented for TS. Since Flow's parser produces AST with the same name, it automatically works. For infer type, we also reuse the existing printTypeParameter function.For testing, I copy the conditional type test suite from TS, and deleted some syntax Flow doesn't support yet (type assertion), and run both Flow and TS prettier on it and ensure they are consistent. I moved the comment one into another suite, because the results are different.
Checklist
docs/directory).changelog_unreleased/*/XXXX.mdfile followingchangelog_unreleased/TEMPLATE.md.✨Try the playground for this PR✨