refactor(web): port the docs type generator to the typescript 7 api

[kianbazza]

Summary

 build-types-meta.ts
-import ts from 'typescript5'                     # TS 5 compiler API
+import { API, … } from 'typescript/unstable/sync' # TS 7 API (talks to the Go checker)
+import { isInterfaceDeclaration, … } from 'typescript/unstable/ast'

 main
-  ts.createProgram({ rootNames, options })
+  new API() → write .tsconfig.types-meta.<pid>.json (extends --tsconfig, files = entries)
+            → updateSnapshot({ openProjects }) → project.program / project.checker
+  finally: api.close(), remove the temp tsconfig

 apps/web/package.json
-  "typescript5": "npm:typescript@5.9.3"

The generator's logic and output schema are unchanged. What changed is how it reaches TypeScript. TypeScript 7 has no classic compiler API; its checker runs in a separate process that typescript/unstable/sync talks to. The port maps each call across:

• Declarations come back as handles that resolve to AST nodes.
• Docs and JSDoc tags come back as strings.
• typeToString takes the TypeFormatFlags values as numbers, since TS 7 doesn't export the enum.
• Diagnostics are formatted locally.

The analysis project is a throwaway tsconfig next to apps/web/tsconfig.json, so extends, paths and type roots resolve as before. It's gitignored and removed on exit, on failure, and on Ctrl-C.

Three places reproduce TypeScript 5 behaviour that TypeScript 7 doesn't share, so the docs tables stay the same:

• Prop order. TS 7 lists an interface's inherited props first. propertyOrder restores TS 5's order: the interface's own members in source order, then each base in extends order.
• Inherited descriptions. An undocumented prop that redeclares an inherited one takes the base's docs, using TS 5's rule. For example, DropdownMenuRootProps.children keeps Base UI's Popover description.
• Type definitions. These are printed from source text, because TS 7's printer drops comments. For example, ColumnDataType's annotated union.

Evidence

• Before: bun run docs:type-gen needs typescript5 (TypeScript 5.9.3) next to TypeScript 7.
  After: it runs on TypeScript 7 only, in about 3 s (same as before), and produces identical output on repeated runs.
• types-meta.json was compared against the previous generator's output on the same sources. Union and intersection members were compared as sets and everything else in order:
  • The same 490 types and 2,151 props. required, default, shortType, enum members and their valueType, typeParams and type docs are all identical. No union member or argument changed.
  • 393 type/formattedType strings differ only in union member order: TS 7 orders unions differently, e.g. ((props, state) => ReactElement) | ReactElement.
  • 45 definitions now use source formatting: repo indentation, no semicolons, comments kept.
  • 29 tables list props in a different order. All of them are Pick/Omit-derived types such as CheckboxItemDef, ComboboxSurfaceProps, SelectSurfaceProps and the registry Filter*Props, where TS 5's order was effectively arbitrary. Component *Props tables like DropdownMenuItemProps and ComboboxItemProps are unchanged.
  • 4 *SurfaceProps.children now show "Children (Input, List, etc.)" where they had no description.
  • 3 "View …" links move because they follow the first member of a union: BreadcrumbNode.node, and content on DropdownMenuSurfaceProps / SelectSurfaceProps.

Merge Danger

Door: two-way

Revert to restore the TS 5 generator (and re-add the typescript5 alias).

Blast Radius: docs type tables

The docs render types-meta.json directly, so the order and description changes above are visible on the component API pages. typescript/unstable/* can change in any TypeScript release; typescript is pinned to 7.0.2 exactly, and a TypeScript bump should re-run docs:type-gen and diff the output.

Closes UI-627

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Project	Deployment	Actions	Updated
ui-canary	Ready	Preview	Sep 29, 2026 2:55pm UTC

[linear-code]

UI-627