toTypeReExports maps every type import in a module to an export type { ... } specifier without collapsing duplicates. dedupeImports keeps class, enum and const enum imports un-collapsed so a value and a type entry of the same declaration can coexist, which means the same type name can reach this step more than once. When it does, the generated re-export lists it twice:

import { createUnimport } from 'unimport'

const { generateTypeDeclarations } = createUnimport({
  imports: [
    { name: 'Foo', from: 'module.js', type: true, declarationType: 'class' },
    { name: 'Foo', from: 'module.js', type: true, declarationType: 'class' },
  ],
})

await generateTypeDeclarations()
// // for type re-export
// declare global {
//   // @ts-ignore
//   export type { Foo, Foo } from 'module'
//   import('module')
// }

export type { Foo, Foo } is a duplicate identifier (TS2300). It is currently suppressed because the line sits under the existing // @ts-ignore, but the output is still malformed. toExports got the same dedupe in #529; this brings the type re-export in line.

The change collapses entries by their re-exported name (as ?? name) before joining, so distinct names and aliases are untouched. The added test reproduces the duplicate: reverting only the source change makes it fail with export type { Foo, Foo }, and the full suite stays green.

Summary by CodeRabbit

• Bug Fixes
  • Type re-exports now avoid duplicate entries when multiple imports refer to the same exported name.
  • Generated export statements are cleaner and no longer repeat the same type specifier.
• Tests
  • Added coverage to verify duplicate type re-exports are collapsed into a single entry.