fix: disable experimental decorator flag #1828
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The `experimentalDecorators` flag is legacy from TypeScript 3.9. Since then, decorators have gone through a large change and their new syntax, which is enabled by default in TypeScript 5+, looks very different. Keeping this old flag enabled locks users into old decorator typings which are deprecated, plus because of the way our defaults are applied these flags are not overridable. Instead, don't set `experimentalDecorators` at all, and have users opt in to legacy syntax if they must. This is technically breaking, but I'm pretty sure this will affect such a negligible fraction of users that I think it's worth it.
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Let's be sure to merge this when we do TypeScript 5.8 |
mrgrain
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Mar 13, 2025
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Oct 6, 2025
This upgrades jsii to a version with support for type intersections. Changes around decorators: * Because this is switching to a newer version of jsii [that doesn't set `experimentalDecorators: true` anymore by default](aws/jsii-compiler#1828), we need to update the typing for the `@MethodMetadata` decorator ([ref](https://devblogs.microsoft.com/typescript/announcing-typescript-5-0/#decorators)). * Because the `framework-integ` package can see the source `.ts` files from `aws-cdk-lib`, it can see the presence of the decorators. The code must type check, so we must switch `experimentalDecorators` to the same value in that package (`false`). Some example code used a legacy decorator which had to be rewritten to be somewhat equivalent: the exact example cannot be recreated with modern decorators. * The emulation of modern decorators behaves slightly differently depending on the target (it either uses the `static { }` JS syntax if available in ES2022+, or tries to emulate that syntax). If the behavior is emulated, the `CONSTRUCT_INJECTION_ID` property can never be read from the class -- it always shows up as `undefined`. Upgrade to ES2022 across the board to generate the right polyfill code. This is supported by Node 16+. * Jsii forces ES2020 by default. To switch everything to ES2022, we need to eject from the jsii autogenerated config everywhere. I also bumped the Node type definitions, which led to a couple more eslint violations that needed to be fixed. ---- *By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*
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The
experimentalDecoratorsflag is legacy from TypeScript 3.9.Since then, decorators have gone through a large change and their new syntax, which is enabled by default in TypeScript 5+, looks very different.
Keeping this old flag enabled locks users into old decorator typings which are deprecated, plus because of the way our defaults are applied these flags are not overridable.
Instead, don't set
experimentalDecoratorsat all, and have users opt in to legacy syntax if they must.This is technically breaking, but I'm pretty sure this will affect such a negligible fraction of users that I think it's worth it.
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.