Introducing @typespec/http-client-js

[joheredi]

This PR introduces the new JavaScript emitter under the package @typespec/http-client-js. This emitter is built using @alloy-js and the new Emitter Framework, leveraging its structured and modular approach for code generation.

[azure-sdk]

All changed packages have been documented.

• ✅ @typespec/compiler
• ✅ @typespec/emitter-framework
• ✅ @typespec/http-client

Show changes

@typespec/compiler - fix ✏️

Export missing type DiscriminatedUnionLegacy

@typespec/http-client - feature ✏️

Improvements to HttpClient context provider

@typespec/emitter-framework - fix ✏️

Improvements on the TestHarness

[azure-sdk]

You can try these changes here

🛝 Playground	🌐 Website	🛝 VSCode Extension

[timotheeguerin]

Did you meant to have this emitter part of our workspace, in this case it probably shouldn't have it own CI as it should run as part of the workspace CI

[joheredi]

Spoke with Tim offline, we'll keep the emitter outside of the workspace and will bring it in once TypeSpec goes 1.0.0

Edit: Had a further discussion with Tim, and we’ve decided that keeping the emitter within the workspace provides a faster development feedback loop. We’ll aim to retain it within the workspace while being cautious of the risks given how close we are to release.

We'll hold off on merging this PR until Tuesday, and in the meantime, I’ll gather some data to assess its impact on CI runs. As a preliminary measurement, running pnpm test:e2e—which involves generating 52 Spector specs and executing all Spector tests—takes under a minute on a dev machine (44 seconds for spec generation, 8 seconds for test execution). I’ll collect similar CI data for comparison.