feat(wasm): universal support with esm import syntax

[pi0]

🔗 Linked issue

❓ Type of change

• 📖 Documentation (updates to the documentation, readme, or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

This PR unifies WASM support using Nitro's built-in wasm plugin and simplified ESM import syntax: (Following ES Module Integration Proposal for WebAssembly)

Using dynamic imports:

export default defineLazyEventHandler(async () => {
  const { sum } = await import("~/wasm/sum.wasm");
  return eventHandler(() => {
    return `2+3=${sum(2, 3)}`;
  });
});

Using static imports: (1)

import { sum } from "~/wasm/sum.wasm";

export default eventHandler(() => {
  return `2+3=${sum(2, 3)}`;
});

• On Node.js and platforms yet not supporting native .wasm imports, Nitro by default creates a base64 inlined version (in a chunk) and instantiates the module
• On supported platforms (Cloudflare pages and modules), plugin will use native wasm import and copy the asset to output

(1) One of the main blockers, are worker targets that don't support top level await, combined with rollup limitation with inlineDynamicImports we cannot use top level await for await WebAssembly.instantiate. This mainly affects/breaks Vercel Edge target. Internally we support wasm.lazy flag that causes to avoid depending on top-level wait for maximise compatibility. It requires static import slight syntax change to work universally again:

import _mod from "~/wasm/sum.wasm";

export default eventHandler(async () => {
  const { sum } = await _mod;
  return `2+3=${sum(2, 3)}`;
});

The value of _mod is a virtual Promise-like that lazily get's evaluated. Hopefully at some point we don't require this syntax change too.

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[pi0]

Merging to make it testable via edge-channel. Feedbacks more than welcome specially @antfu @harlan-zw since I know you have some good projects to verify against.

[pi0]

Early checking against shikiji, seems some issues

[antfu]

Looks awesome! Will give a try tmr