Fix for import type statement causes optimizeImports error carbon-design-system#80 [carbon-design-system#80]

Author: aleksan27

Diff for: src/preprocessors/optimize-imports.ts

@@ -32,7 +32,7 @@ export const optimizeImports: SveltePreprocessor<"script"> = () => {
       if (/node_modules/.test(filename)) return;
 
       // Wrap the content in a `<script>` tag to parse it with the Svelte parser.
-      const content = `<script>${raw}</script>`;
+      const content = `<script lang="ts">${raw}</script>`;
       const s = new MagicString(content);
 
       walk(parse(content), {
@@ -60,7 +60,7 @@ export const optimizeImports: SveltePreprocessor<"script"> = () => {
         },
       });
 
-      s.replace(/^<script>/, "");
+      s.replace(/^<script lang="ts">/, "");
       s.replace(/<\/script>$/, "");
 
       return {

Diff for: tests/optimize-imports.test.ts

@@ -138,4 +138,18 @@ import Analytics from "carbon-pictograms-svelte/lib/Analytics.svelte";`);
           import Accordion from "carbon-components-svelte/src/Accordion/Accordion.svelte";
         `);
   });
+
+  test("import type statements should be preserved", () => {
+    expect(
+      preprocess({
+        content: `
+          import { Theme } from "carbon-components-svelte";
+          import type { CarbonTheme } from "carbon-components-svelte/src/Theme/Theme.svelte";
+        `,
+      }),
+    ).toEqual(`
+          import Theme from "carbon-components-svelte/src/Theme/Theme.svelte";
+          import type { CarbonTheme } from "carbon-components-svelte/src/Theme/Theme.svelte";
+        `);
+  });
 });