feat: Update Exports type and add getExports function

This commit updates the Exports type in type.ts to include an optional
object with a '.' key. It also adds a new function getExports in utils.ts
which generates the exports field for JSR from package.json. The function
handles different formats of the exports field in package.json and converts
them into a suitable format for JSR. Error handling is also added for
unsupported formats.

src/type.ts

@@ -1,4 +1,4 @@
-export type Exports = Record<string, string> | string;
+export type Exports = Record<string, string> | { '.': string };
 
 export type JSR = {
 	name: string;
@@ -7,5 +7,5 @@ export type JSR = {
 		include: string[] | undefined;
 		exclude: string[] | undefined;
 	};
-	exports: Exports;
+	exports: Exports | undefined;
 };

src/utils.ts

@@ -1,6 +1,7 @@
 import typia from 'typia';
 import type { PackageJson } from 'pkg-types';
-import type { JSR } from './type';
+import consola from 'consola';
+import type { Exports, JSR } from './type';
 
 const isStartWithExclamation = typia.createIs<`!${string}`>();
 
@@ -31,7 +32,108 @@ export function getExclude(pkgJSON: PackageJson): string[] | undefined {
 		});
 }
 
-export function genJsrFromPkg({ pkgJSON, options }: { pkgJSON: PackageJson; options: PkgToJsrConfig }): JSR {
+/**
+ * generate exports filed for JSR from package.json
+ * the import path should be string, { source: string }, { import: string }
+ *
+ * @example
+ * ```json
+ * {
+ *   "exports": './index.js',
+ * }
+ * ```
+ * will get coverted into
+ * ```json
+ * {
+ *   "exports": {
+ *     ".": "./index.js"
+ *   }
+ * }
+ * ```
+ *
+ * @example
+ * ```json
+ * {
+ *   "exports": {
+ *     ".": "./index.js",
+ *     "./sub": "./sub.js"
+ *   }
+ * }
+ * ```
+ * will get coverted into
+ * ```json
+ * {
+ *   "exports": {
+ *     ".": "./index.js",
+ *     "./sub": "./sub.js"
+ *   }
+ * }
+ * ```
+ *
+ * @example
+ * ```json
+ * {
+ *   "exports": {
+ *     ".": {
+ *       "source": "./src/index.ts",
+ *       "import": "./dist/index.js"
+ *       "types": "./dist/index.d.ts"
+ *     },
+ *     "./sub": {
+ *       "source": "./src/sub.ts"
+ *       "import": "./dist/sub.js"
+ *       "types": "./dist/sub.d.ts"
+ *	   }
+ *   }
+ * }
+ * ```
+ * will get coverted into
+ * ```json
+ * {
+ *   "exports": {
+ *     ".": "./src/index.ts",",
+ *     "./sub": "./src/sub.ts"
+ *   }
+ * }
+ * ```
+ */
+export function getExports(pkgJSON: PackageJson): Exports | undefined {
+	const { exports } = pkgJSON;
+
+	if (exports == null) {
+		return;
+	}
+
+	if (typia.is<string>(exports)) {
+		return { '.': exports };
+	}
+
+	const _exports = {} as Record<string, string>;
+
+	for (const [key, value] of Object.entries(exports)) {
+		switch (true) {
+			case typia.is<string>(value):
+				_exports[key] = value;
+				break;
+			case typia.is<Record<string, string>>(value):
+				/* if source is defined, use it, otherwise use import */
+				_exports[key] = value.source ?? value.import;
+				break;
+			default:
+				consola.error(`Export key ${key} is ignored because it is not a string or object`);
+		}
+	}
+
+	if (Object.keys(_exports).length === 0) {
+		return;
+	}
+
+	return _exports;
+}
+
+/**
+ * generate JSR from package.json
+ */
 export function genJsrFromPkg({ pkgJSON }: { pkgJSON: PackageJson }): JSR {
 	const { name, version } = pkgJSON;
 	const jsr = {
@@ -41,7 +143,7 @@ export function genJsrFromPkg({ pkgJSON }: { pkgJSON: PackageJson }): JSR {
 			include: getInclude(pkgJSON),
 			exclude: getExclude(pkgJSON),
 		},
-		exports: options.exports,
+		exports: getExports(pkgJSON),
 	} as const satisfies JSR;
 
 	/* check the JSR object */