fix(transformer/decorator): do not lose WeakMap when decorator and class properties transforms combined

[overlookmotel]

Closes #9171.

Prevent injected statements attached to the Class statement getting lost when class C {} is replaced with let C = class C {}; by moving them to be attached to the new let C statement.

---

I'm actually unclear why we have to transform class C {} to let C = class C {}; anyway. class C {} already creates a binding C which behaves like a let binding, so it can be reassigned.

Input:

@dec
export class C {}

Current output:

let C = class C {};
C = babelHelpers.decorate([dec], C);
export { C };

Could just be:

export class C {}
C = babelHelpers.decorate([dec], C);

ESBuild does this - it keeps the class declaration.

[overlookmotel]

• fix(transformer): TransformOptions::enable_all enable decorator transform #9946
• fix(transformer/decorator): do not lose WeakMap when decorator and class properties transforms combined #9952 👈 (View in Graphite)
• feat(transformer): add StatementInjectorStore::move_insertions method #9951
• refactor(transformer/decorator): rename enter_statement to exit_statement #9950
• main

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[codspeed-hq]

CodSpeed Instrumentation Performance Report

Merging #9952 will create unknown performance changes

_{Comparing 03-21-fix_transformer_decorator_do_not_lose_weakmap_when_decorator_and_class_properties_transforms_combined (c7fc700) with main (ffd4d13)}

Summary

🆕 33 new benchmarks

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
🆕	codegen[checker.ts]	N/A	22.6 ms	N/A
🆕	codegen_sourcemap[checker.ts]	N/A	65.7 ms	N/A
🆕	isolated-declarations[vue-id.ts]	N/A	58.3 ms	N/A
🆕	lexer[RadixUIAdoptionSection.jsx]	N/A	21.4 µs	N/A
🆕	lexer[antd.js]	N/A	24.8 ms	N/A
🆕	lexer[cal.com.tsx]	N/A	5.9 ms	N/A
🆕	lexer[checker.ts]	N/A	14.8 ms	N/A
🆕	lexer[pdf.mjs]	N/A	3.9 ms	N/A
🆕	linter[RadixUIAdoptionSection.jsx]	N/A	2.7 ms	N/A
🆕	linter[cal.com.tsx]	N/A	1.2 s	N/A
🆕	linter[checker.ts]	N/A	3 s	N/A
🆕	mangler[antd.js]	N/A	15.8 ms	N/A
🆕	mangler[react.development.js]	N/A	291.8 µs	N/A
🆕	mangler[typescript.js]	N/A	39.2 ms	N/A
🆕	minifier[antd.js]	N/A	165.2 ms	N/A
🆕	minifier[react.development.js]	N/A	1.8 ms	N/A
🆕	minifier[typescript.js]	N/A	290.9 ms	N/A
🆕	estree[checker.ts]	N/A	96.1 ms	N/A
🆕	parser[RadixUIAdoptionSection.jsx]	N/A	92.5 µs	N/A
🆕	parser[antd.js]	N/A	113.3 ms	N/A
...	...	...	...	...

ℹ️ Only the first 20 benchmarks are displayed. Go to the app to view all benchmarks.

[Dunqing]

Your esbuild configuration is wrong, the decorator is treated as ES Decorator, you should set loader=ts and turn on experimentDecorator

The correct example is
https://esbuild.github.io/try/#dAAwLjI0LjAALS10YXJnZXQ9ZXMyMDIwIC0tbG9hZGVyPXRzICItLXRzY29uZmlnLXJhdz17XCJjb21waWxlck9wdGlvbnNcIjp7XCJleHBlcmltZW50YWxEZWNvcmF0b3JzXCI6dHJ1ZX19IgBAZGVjKCkKY2xhc3MgRm9vIHsKICAjYmFyID0gImJhciI7CiAgdGVzdCgpIHsgcmV0dXJuIHRoaXMuI2JhcjsgfQp9Cg

[overlookmotel]

Your esbuild configuration is wrong

Shame on me!

Thanks for pointing that out. Odd that ESBuild produces less optimal output for legacy decorators. But, regardless of what ESBuild does, I think retaining the class C declaration would be perfectly valid (and is shorter).

[Dunqing]

Merge activity

• Mar 21, 10:07 AM EDT: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Mar 21, 10:07 AM EDT: A user added this pull request to the Graphite merge queue.
• Mar 21, 10:18 AM EDT: A user merged this pull request with the Graphite merge queue.