Calculate and emit "idle" event only when testing

Only some tests rely on the "idle" event. Push/Shift operations on the idleStack introduce extra work (O(N)) in order to calculate the idle status. This kind of routine work should not affect the rate calculation process which is required to be as fast as possible.

src/system/consumer/consumer-message-rate.ts

@@ -17,10 +17,6 @@ export class ConsumerMessageRate extends MessageRate<IConsumerMessageRateFields>
   protected unacknowledgedRate = 0;
   protected idleStack: number[] = new Array(5).fill(0);
 
-  // When the idle status is true, it indicates that the consumer has been
-  // inactive for the last 5 seconds
-  protected isIdle = false;
-
   constructor(consumer: Consumer, redisClient: RedisClient) {
     super(redisClient);
     this.consumer = consumer;
@@ -34,6 +30,22 @@ export class ConsumerMessageRate extends MessageRate<IConsumerMessageRateFields>
     this.keyConsumerRateUnacknowledged = keyRateConsumerUnacknowledged;
   }
 
+  // Returns true if the consumer has been
+  // inactive for the last 5 seconds
+  isIdle(): boolean {
+    if (
+      this.processingRate === 0 &&
+      this.acknowledgedRate === 0 &&
+      this.unacknowledgedRate === 0
+    ) {
+      this.idleStack.push(1);
+    } else {
+      this.idleStack.push(0);
+    }
+    this.idleStack.shift();
+    return this.idleStack.find((i) => i === 0) === undefined;
+  }
+
   getRateFields(): IConsumerMessageRateFields {
     this.processingRate = this.processingSlots.reduce(
       (acc: number, cur: number) => acc + cur,
@@ -50,23 +62,13 @@ export class ConsumerMessageRate extends MessageRate<IConsumerMessageRateFields>
       0,
     );
     this.unacknowledgedSlots.fill(0);
-    if (
-      this.processingRate === 0 &&
-      this.acknowledgedRate === 0 &&
-      this.unacknowledgedRate === 0
-    ) {
-      this.idleStack.push(1);
-    } else {
-      this.idleStack.push(0);
+    if (process.env.NODE_ENV === 'test' && this.isIdle()) {
+      this.consumer.emit(events.IDLE);
     }
-    this.idleStack.shift();
-    this.isIdle = this.idleStack.find((i) => i === 0) === undefined;
-    if (this.isIdle) this.consumer.emit(events.IDLE);
     return {
       processingRate: this.processingRate,
       acknowledgedRate: this.acknowledgedRate,
       unacknowledgedRate: this.unacknowledgedRate,
-      isIdle: this.isIdle,
     };
   }
 

types/index.ts

@@ -53,7 +53,6 @@ export interface IConsumerMessageRateFields
   acknowledgedRate: number;
   unacknowledgedRate: number;
   processingRate: number;
-  isIdle: boolean;
 }
 
 export interface IProducerMessageRateFields extends Record<string, number> {