29. Countdown Timer

HTML

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<div id="app" aria-live="polite"></div>

JavaScript

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/* Use state-based UI to create the timer, and countdown from 60 seconds to 0 once a second. 
When the timer is done, stop the countdown and provide a way for users to start it again. */

const timeValue = 6;
const Rue = function (selector, options) {
  this.elem = document.querySelector(selector);
  this.data = options.data;
  this.template = options.template;
};
Rue.prototype.render = function () {
  this.elem.innerHTML = this.template(this.data);
};
  Rue.prototype.restartTimer = function () {
    this.data.time = timeValue;
    app.timer()
}
Rue.prototype.stopTimer = function () {
  this.elem.innerHTML = `<h2>It's over, start again:</h2><button onclick="app.restartTimer()" class="button">Start Again</button>`
}
Rue.prototype.timer = function () {
  const intervalCount = window.setInterval(function () {
    if(!app) return;
    app.data.time--
    app.render();
    if (app.data.time < 1) {
      window.clearInterval(intervalCount)
      app.stopTimer()
    }
  }, 1000);
    app.render();
};
const app = new Rue('#app', {
  data: {
    time: timeValue,
  },
  template: function (props) {
    if (!props) return;
    let html = `<h2>You've got only <span class="counter">${props.time}</span> seconds!</h2>`;
    return html;
  }
})
app.timer();