Check for undefined peekCommand queue entry

packages/memcache-client/src/lib/connection.ts

@@ -225,14 +225,16 @@ export class MemcacheConnection extends MemcacheParser {
   receiveResult(pending: ParserPendingData): void {
     if (this.isReady()) {
       const retrieve = this.peekCommand();
-      try {
-        retrieve.results[pending.cmdTokens[1]] = {
-          tokens: pending.cmdTokens,
-          casUniq: pending.cmdTokens[4],
-          value: this.client?._unpackValue(pending as unknown as PackedData),
-        };
-      } catch (err) {
-        retrieve.error = err as Error;
+      if (retrieve) {
+        try {
+          retrieve.results[pending.cmdTokens[1]] = {
+            tokens: pending.cmdTokens,
+            casUniq: pending.cmdTokens[4],
+            value: this.client?._unpackValue(pending as unknown as PackedData),
+          };
+        } catch (err) {
+          retrieve.error = err as Error;
+        }
       }
     }
     delete pending.data;

packages/memcache-client/src/test/spec/connection.spec.ts

@@ -119,4 +119,16 @@ describe.only("MemcacheConnection", function () {
     );
     x._shutdown("test");
   });
+
+  it("receiveResult should not crash when peekCommand returns undefined", () => {
+    const x = new MemcacheConnection({ socketID: 1 } as unknown as MemcacheClient);
+    x._status = Status.READY;
+    x.peekCommand = () => undefined as any;
+    expect(() => {
+      x.receiveResult({
+        cmdTokens: ["VALUE", "testkey", "0", "5"],
+        key: "testkey",
+      });
+    }).not.toThrow();
+  });
 });