chore: include exporting as default logic

src/builders/rollup/build.ts

@@ -9,7 +9,7 @@ import { getRollupOptions } from "./config";
 import { getChunkFilename } from "./utils";
 import { rollupStub } from "./stub";
 import { rollupWatch } from "./watch";
-import { fixCJSExportTypePlugin } from "./plugins/cjs";
+import { fixDefaultCJSExportsPlugin } from "./plugins/cjs";
 
 export async function rollupBuild(ctx: BuildContext): Promise<void> {
   // Stub mode
@@ -82,7 +82,7 @@ export async function rollupBuild(ctx: BuildContext): Promise<void> {
       ...rollupOptions.plugins,
       dts(ctx.options.rollup.dts),
       removeShebangPlugin(),
-      ctx.options.rollup.emitCJS && fixCJSExportTypePlugin(),
+      ctx.options.rollup.emitCJS && fixDefaultCJSExportsPlugin(ctx),
     ].filter(Boolean);
 
     await ctx.hooks.callHook("rollup:dts:options", ctx, rollupOptions);

src/builders/rollup/plugins/cjs.md

@@ -0,0 +1,129 @@
+# Default CJS exports
+
+This document will cover all the types of default exports that can be generated by [rollup-plugin-dts](https://github.com/Swatinem/rollup-plugin-dts) plugin.
+
+### Export default without specifier from the module itself (index.ts in the fixture)
+
+The following example can be found in the [reexport-types](../../../../test/cjs-types-fixture/reexport-types) fixture, check `index.ts` module.
+
+Given the following code:
+```ts
+// module.ts
+export default function foo() {}
+```
+
+`rollup-plugin-dts` will generate:
+```ts
+// module.d.[c]ts
+declare function foo(): void;
+
+export { foo as default };
+```
+
+we need to convert it to:
+```ts
+// module.d.[c]ts
+declare function foo(): void;
+
+export = foo;
+```
+
+### Exporting default from default import
+
+The following example can be found in the [reexport-default](../../../../test/cjs-types-fixture/reexport-default) fixture, check `index.ts` module.
+
+Given the following code:
+```ts
+// module.ts
+import MagicString from "magic-string";
+export default MagicString;
+```
+
+`rollup-plugin-dts` will generate:
+```ts
+// module.d.[c]ts
+import MagicString from 'magic-string';
+export { default } from 'magic-string';
+```
+
+we need to convert it to (doesn't require adding the import):
+```ts
+// module.d.[c]ts
+import MagicString from 'magic-string';
+export = MagicString;
+```
+
+### Exporting default with specifier
+
+The following example can be found in the [reexport-types](../../../../test/cjs-types-fixture/reexport-types) fixture, check `all.ts` module.
+
+Given the following code:
+```ts
+// module.ts
+export type * from "./index.ts";
+export { default } from "./index.ts";
+```
+
+`rollup-plugin-dts` will generate:
+```ts
+// module.d.[c]ts
+// otherexports and otherexporttypes when present
+export { otherexports, type otherexporttypes, default } from './index.js';
+```
+
+we need to convert it to (requires adding the import):
+```ts
+// module.d.[c]ts
+import _default from './index.js';
+export = _default;
+// otherexports and otherexporttypes when present
+export { otherexports, type otherexporttypes } from './index.js';
+```
+
+### Exporting default from named import as default export with specifier
+
+The following example can be found in the [reexport-default](../../../../test/cjs-types-fixture/reexport-default) fixture, check `asdefault.ts` module.
+
+Given the following code:
+```ts
+// module.ts
+import { resolve } from "pathe";
+export default resolve;
+```
+
+`rollup-plugin-dts` will generate:
+```ts
+// module.d.[c]ts
+import { resolve } from 'pathe';
+export { resolve as default } from 'pathe';
+```
+
+we need to convert it to (doesn't require adding the import):
+```ts
+// module.d.[c]ts
+import { resolve } from 'pathe';
+export = resolve;
+```
+
+### Exporting named export as default with specifier
+
+The following example can be found in the [reexport-default](../../../../test/cjs-types-fixture/reexport-default) fixture, check `asdefault.ts` module.
+
+Given the following code:
+```ts
+// module.ts
+export { resolve as default } from "pathe";
+```
+
+`rollup-plugin-dts` will generate:
+```ts
+// module.d.[c]ts
+export { resolve as default } from 'pathe';
+```
+
+we need to convert it to (requires adding the import):
+```ts
+// module.d.[c]ts
+import { resolve } from 'pathe';
+export = resolve;
+```