Import typescript files with `bring`

[MarkMcCulloh]

Use Case

The current mechanism to import javascript/typescript is extern. Among several DX issues, a primary difficulty is that it forces the user to declare types for the module upfront within the consuming wing file. This takes the source of truth for types away from the implementation. Instead, we can import typescript files like wing files to allow them to be the source of truth:

bring "helper.ts" as helper;

Proposed Solution

To limit the implementation difficulty, I would propose the following limitations/simplifications:

• ESM only (either implicitly or only allowing .mts)
  • Parsing ESM to find exports is much simpler than CJS
• Named exports only
• async translates to inflight
• exports can be classes, functions, interfaces, or enums
• Extremely limited types:
  • primitives with equivalent wing types
  • No re-exporting of imported types
  • No builtin global types
  • classes and interfaces (no references to imported types)
  • Classes are always inflight
  • arrays of supported types
  • literal objects of supported types

Ideally, the naive implementation of

1. Parse single typescript file
2. Visit all exports to build up a wing SymbolEnv with type info

The above restrictions basically already match existing extern restrictions.

Implementation Notes

Depends on https://github.com/winglang/wing/issues/3013 to run ESM+typescript in preflight.

https://docs.rs/oxc_parser/latest/oxc_parser/ and https://docs.rs/oxc_semantic/latest/oxc_semantic/ could be invaluable here

Component

No response

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