Fix minify-whitespace `case undefined` (#6808)

Print a space before `undefined` in `printUndefined`.

fix https://github.com/oven-sh/bun/issues/6750

2 files changed, 21 insertions, 0 deletions

diff --git a/src/js_printer.zig b/src/js_printer.zig
index d81499a36..f0ea20c34 100644
--- a/src/js_printer.zig
+++ b/src/js_printer.zig
@@ -981,6 +981,7 @@ fn NewPrinter(
                     p.print("void 0");
                 }
             } else {
+                p.printSpaceBeforeIdentifier();
                 p.addSourceMapping(loc);
                 p.print("undefined");
             }
diff --git a/test/bundler/bundler_minify.test.ts b/test/bundler/bundler_minify.test.ts
index fb6b8db7a..7e1c7ec12 100644
--- a/test/bundler/bundler_minify.test.ts
+++ b/test/bundler/bundler_minify.test.ts
@@ -307,4 +307,24 @@ describe("bundler", () => {
       stdout: "PASS",
     },
   });
+  // https://github.com/oven-sh/bun/issues/6750
+  itBundled("minify/SwitchUndefined", {
+    files: {
+      "/entry.js": /* js */ `
+        switch (1) {
+          case undefined: {
+          }
+        }
+        console.log("PASS");
+      `,
+    },
+    minifyWhitespace: true,
+    minifySyntax: false,
+    minifyIdentifiers: false,
+    target: "bun",
+    backend: "cli",
+    run: {
+      stdout: "PASS",
+    },
+  });
 });