9. Event-Driven Programming and Built-In Modules

Activity 13: Building an Event-Driven Module

Solution:

Perform the following steps to complete this activity:

1. Import the events module:

   const EventEmitter = require('events');

2. Create the SmokeDetector class that extends EventEmitter and set batteryLevel to 10:

   class SmokeDetector extends EventEmitter {
       constructor() {
           super();
           this.batteryLevel = 10;
       }
   }

   In our constructor, because we are extending the EventEmitter class and we are assigning a custom property, batteryLevel, we will need to call super inside the constructor and set batteryLevel to 10.

3. Create a test method inside the SmokeDetector class that will test the battery level and emit a low battery message in the event that the battery is low:

   test() {
           if (this...