first commit

transpileTs.ts

@@ -0,0 +1,80 @@
+import { contentType } from "jsr:@std/media-types";
+import { transpile } from "jsr:@deno/emit";
+import config from "./deno.json" with { type: "json" };
+
+const jsContentType = contentType(".js");
+
+export enum MediaType {
+    TypeScript,
+    JSX,
+    TSX,
+};
+
+// https://github.com/denoland/deno_ast/blob/ea1ccec37e1aa8e5e1e70f983a7ed1472d0e132a/src/media_type.rs#L117
+const customContentType = {
+    [MediaType.TypeScript]: "text/typescript; charset=utf-8",
+    [MediaType.JSX]: "text/jsx; charset=utf-8",
+    [MediaType.TSX]: "text/tsx; charset=utf-8",
+};
+
+async function rewriteTsResponse(response: Response, url: URL, mediaType: MediaType) {
+    const tsCode = await response.text();
+    const targetUrlStr = url.toString();
+    try {
+        const result = await transpile(url, {
+            importMap: config,
+            compilerOptions: config.compilerOptions,
+            load(specifier) {
+                if (specifier !== targetUrlStr) {
+                    return Promise.resolve({
+                        kind: "module",
+                        specifier,
+                        content: "",
+                        headers: { "content-type": "application/javascript; charset=utf-8" },
+                    });
+                } else {
+                    return Promise.resolve({
+                        kind: "module",
+                        specifier,
+                        content: tsCode,
+                        headers: {
+                            "content-type": customContentType[mediaType],
+                        },
+                    });
+                }
+            },
+        });
+        const jsCode = result.get(targetUrlStr);
+        const { headers } = response;
+        headers.set("content-type", jsContentType);
+        headers.delete("content-length");
+
+        return new Response(jsCode, {
+            status: response.status,
+            statusText: response.statusText,
+            headers,
+        });
+    } catch (e) {
+        console.error(e);
+        return new Response(`${e}`, {
+            status: 500,
+            statusText: `${e}`,
+            headers: response.headers,
+        });
+    }
+}
+
+export default async function transpileResponse(response: Response, requestUrl: string, filepath?: string): Promise<Response> {
+    const url = new URL(`ts-serve:///${ requestUrl }`);
+    if (response.status !== 200) {
+        return response;
+    }
+    const pathname = filepath !== undefined ? filepath : url.pathname;
+    const extension = pathname.split('.').at(-1) ?? null;
+    switch (extension) {
+        case 'ts': return await rewriteTsResponse(response, url, MediaType.TypeScript);
+        case 'tsx': return await rewriteTsResponse(response, url, MediaType.TSX);
+        case 'jsx': return await rewriteTsResponse(response, url, MediaType.JSX);
+        default: return response;
+    }
+}