fix(unpkg): only perform GENERATION rewriting for old versions that s…

…till have generation support

src/unpkg.mjs

@@ -52,10 +52,14 @@ async function transformBody(resp, responseUrl, req) {
   if (resp.ok
     && resp.status === 200
     && url.pathname.indexOf('@adobe/helix-rum-js') >= 0) {
-    const generation = url.searchParams.get('generation') || respURL.pathname.split(/[@\\/]/).slice(2, 5).join('-');
-    const text = await resp.text();
-    const body = text.replace(/__HELIX_RUM_JS_VERSION__/, generation.replace(/[^a-z0-9_.-]/ig, ''));
-    return new Response(body, { headers: resp.headers });
+    const urlversion = respURL.pathname.split(/[@\\/]/).slice(2, 5).pop();
+    if (urlversion === '1.0.0' || urlversion === '1.0.1') {
+    // only rewrite for 1.0.0 and 1.0.1 – newer versions don't need this
+      const generation = url.searchParams.get('generation') || respURL.pathname.split(/[@\\/]/).slice(2, 5).join('-');
+      const text = await resp.text();
+      const body = text.replace(/__HELIX_RUM_JS_VERSION__/, generation.replace(/[^a-z0-9_.-]/ig, ''));
+      return new Response(body, { headers: resp.headers });
+    }
   }
   return resp;
 }

test/unpkg.test.mjs

@@ -48,15 +48,26 @@ describe('Test unpkg handler', () => {
 
   it('handles @adobe/helix-rum request', async () => {
     const req = {};
-    req.url = 'http://foo.bar.org/.rum/@adobe/helix-rum-js?generation=42';
+    req.url = 'http://foo.bar.org/.rum/@adobe/helix-rum-js@^1?generation=42';
 
     const storedFetch = global.fetch;
 
     try {
       // Mock the global fetch function
       global.fetch = (v, opts) => {
         assert.equal('unpkg.com', opts.backend);
-        if (v.url === 'https://unpkg.com/@adobe/helix-rum-js') {
+        if (v.url === 'https://unpkg.com/@adobe/helix-rum-js@^1') {
+          const resp = {
+            ok: true,
+            url: v.url,
+            status: 302,
+          };
+          resp.headers = new Headers();
+          resp.headers.append('location', 'https://unpkg.com/@adobe/[email protected]');
+          resp.headers.append('foo-header', 'bar');
+          return resp;
+        }
+        if (v.url === 'https://unpkg.com/@adobe/[email protected]') {
           const resp = {
             ok: true,
             url: v.url,