Frontend

The frontend owns TypeScript-facing semantics.

Responsibilities

• TS Program creation
• core globals injection
• surface profile resolution
• source-package import resolution
• package graph traversal
• validation and diagnostics
• IR construction

Program Creation

Important current behavior:

• compiler core globals are injected virtually
• surface selects the ambient runtime personality
• workspace dotnet.typeRoots is additive
• source-package files under node_modules are included in the same TS Program when resolved

Surface Profiles

Current model:

• builtin clr
• custom/package surfaces via tsonic.surface.json
• resolved surface chains (resolvedModes) for compatibility checks

Example:

• active surface: @acme/surface-node
• resolved modes may include @tsonic/js
• source packages declaring ["@tsonic/js"] can still be accepted

Source Packages

The frontend recognizes installed packages with:

package.json
tsonic/package-manifest.json

and kind:

{ "kind": "tsonic-source-package" }

These are treated as TS source, not opaque module stubs.

Validation Areas

• unsupported/open-world features
• numeric proof
• generic function value determinism
• object literal runtime representability
• import.meta
• dynamic import()
• source-package surface mismatch

Output

Frontend output is IR plus diagnostics, not C#.