Javascript: Timer that rings

JS: Asynchronous programming
Last update: 19 Jan 23:20
0
Students

This practice includes elements of asynchronous programming (setTimeout) since bind is mainly used in this context

timer.js

Implement and export as default a function that returns a timer object. The timer is set for a specific duration and launches. Every 100 milliseconds, it invokes a callback, passing two parameters: state with the working value and elapsedTime that contains the amount of time that has passed since the timer began (in milliseconds). When the timer is over, it calls the same callback with the state parameter and the finished value.

// Callback
const cb = ({ state, elapsedTime }) => {
  switch (state) {
    case 'working':
      console.log(`Time elapsed: ${elapsedTime}`);
      break;
    case 'finished':
      console.log(`Timer has finished!`);
  }
};

// Creates timer object
const timer = makeTimer(300, cb); // Set it up for 300 milliseconds
timer.start();
// Time elapsed: 100
// Time elapsed: 200
// Time elapsed: 300
// Timer has finished!

Tips

  • Timers
  • Use setInterval to start the timer
  • Use clearInterval to refresh it
  • Each new tick should not affect other ticks in any way. The data must be isolated

For full access to the challenge you need a professional subscription.

A professional subscription will give you full access to all Hexlet courses, projects and lifetime access to the theory of lessons learned. You can cancel your subscription at any time.

Get access
130
courses
1000
exercises
2000+
hours of theory
3200
tests