node.js setInterval does not trigger a this. object - node.js

Question

When the page loads the console log part of the function works showing me the current seconds + 3, but it does not repeat and the (innerText =....) does not work at all. I only added the console log part to the code to try to troubleshoot, the inner text change is the important part.
class Main {
constructor() {
// Initiate variables
this.TimerTexts = [];
this.infoTexts = [];
this.training = -1; // -1 when no class is being trained
this.videoPlaying = false;
this.currentTime2 = new Date(Date.now());
this.currentTime = new Date(Date.now());
this.remTime = this.currentTime.getSeconds() + 3;
this.looper = window.setInterval(this.intervalfunc(), 1000);
}
// ...
intervalfunc() {
this.TimerTexts.innerText = `Time: ${this.remTime} `;
console.log(this.remTime);
}
// ...
}

Answer 1

The problem is you're calling intervalfunc, not passing in as the function for setInterval.
In addition, you'll need to bind the function to your instance.
this.looper = window.setInterval(this.intervalfunc.bind(this), 1000);

Answer 2

You can use arrow function, inside arrow function you can call intervalfunc.
class Main {
constructor() {
// Initiate variables
this.TimerTexts = [];
this.infoTexts = [];
this.training = -1; // -1 when no class is being trained
this.videoPlaying = false;
this.currentTime2 = new Date(Date.now());
this.currentTime = new Date(Date.now());
this.remTime = this.currentTime.getSeconds() + 3;
this.looper = window.setInterval(()=>this.intervalfunc(), 1000);
}
intervalfunc() {
this.TimerTexts.innerText = `Time: ${this.remTime} `;
console.log(this.remTime);
this.remTime += 3;
}
}
new Main()
OR you can do
class Main {
constructor() {
// Initiate variables
this.TimerTexts = [];
this.infoTexts = [];
this.training = -1; // -1 when no class is being trained
this.videoPlaying = false;
this.currentTime2 = new Date(Date.now());
this.currentTime = new Date(Date.now());
this.remTime = this.currentTime.getSeconds() + 3;
var self = this;
this.looper = window.setInterval(this.intervalfunc.bind(self), 1000);
}
intervalfunc() {
this.TimerTexts.innerText = `Time: ${this.remTime} `;
console.log(this.remTime);
this.remTime += 3;
}
}
new Main()