fix: remove x-sourcemap header

This header is useless, as the client bundle already contains a sourceMappingURL field. Besides, Firefox prints the following warning: > <url> is being assigned a //# sourceMappingURL, but already has one Related: #3958
socketio · Jul 3, 2021 · a4dffc6 · a4dffc6
1 parent 7c44893
commit a4dffc6
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Showing 2 changed files with 1 addition and 4 deletions.
diff --git a/lib/index.ts b/lib/index.ts
@@ -515,9 +515,6 @@ export class Server<
     );
     res.setHeader("ETag", expectedEtag);
 
-    if (!isMap) {
-      res.setHeader("X-SourceMap", filename.substring(1) + ".map");
-    }
     Server.sendFile(filename, req, res);
   }
 

diff --git a/test/socket.io.ts b/test/socket.io.ts
@@ -59,7 +59,7 @@ describe("socket.io", () => {
             if (err) return done(err);
             expect(res.headers["content-type"]).to.be("application/javascript");
             expect(res.headers.etag).to.be('"' + clientVersion + '"');
-            expect(res.headers["x-sourcemap"]).to.be(filename + ".map");
+            expect(res.headers["x-sourcemap"]).to.be(undefined);
             expect(res.text).to.match(/engine\.io/);
             expect(res.status).to.be(200);
             done();