fix: handle non-existant redis node gracefully

lib/cluster/ConnectionPool.ts

@@ -29,7 +29,7 @@ export default class ConnectionPool extends EventEmitter {
 
   getNodes(role: NodeRole = "all"): Redis[] {
     const nodeRecords = this.nodeRecords[role];
-    return Object.keys(nodeRecords).map((key) => nodeRecords[key].redis);
+    return Object.keys(nodeRecords).map((key) => nodeRecords[key]?.redis);
   }
 
   getInstanceByKey(key: NodeKey): Redis {
@@ -39,7 +39,7 @@ export default class ConnectionPool extends EventEmitter {
   getSampleInstance(role: NodeRole): Redis {
     const keys = Object.keys(this.nodeRecords[role]);
     const sampleKey = sample(keys);
-    return this.nodeRecords[role][sampleKey].redis;
+    return this.nodeRecords[role][sampleKey]?.redis;
   }
 
   /**

test/functional/cluster/ConnectionPool.ts

@@ -0,0 +1,12 @@
+import { expect } from "chai";
+
+import ConnectionPool from "../../../lib/cluster/ConnectionPool";
+
+describe("The cluster connection pool", () => {
+  describe("when not connected", () => {
+    it("does not throw when fetching a sample node", () => {
+      expect(new ConnectionPool({}).getSampleInstance("all")).to.be.undefined;
+      expect(new ConnectionPool({}).getNodes("all")).to.be.eq([]);
+    });
+  });
+});