Javascript Class variable reassign

Question

I am creating a Class instance, I am kinda stuck on variable reassign, like below

class A {
  constructor() {
    this.checkBoolen = false
  }

  checkBoolen = false // error, asks to install @babel/plugin-proposal-class-properties to get support.

  click() {
   document.addEventListener('click', e => {
      this.checkBoolen=true // <- a class constructor's prototype property can't be reassigned.
   })
  }

  doSomthing() {
   if(this.checkBoolen = true // <- never get there) {
    console.log('do something')
       setTimeout(function(){ this.checkBoolen = false}, 3000)
   }
  }
}

Looks like either I need to use @babel/plugin-proposal-class-properties? or change the Class to a function? I am wondering if there is a way to change variable inside Class or it is a bad practice?

If you use arrow functions instead of traditional function then it may solve your issue. This is due to scope of variable will be maintained. — Tejas
– Tejas, Commented Sep 6, 2019 at 6:17

Pranoy Sarkar · Accepted Answer · 2019-09-06 06:06:34Z

1

There are multiple mismatch brackets, class keyword is uppercased

class A {
  constructor() {
    this.checkBoolen = false
  }

   checkBoolen = false // error, asks to install @babel/plugin-proposal-class-properties to get support.

  click() {
   document.addEventListener('click', e => {
      this.checkBoolen=true // <- a class constructor's prototype property can't be reassigned.
   });
  }

  doSomthing() {
   if(this.checkBoolen = true )// <- never get there) {
    console.log('do something')
   }
}

And you can use it like this

let obj = new A();
obj.checkBoolen=true
obj.doSomthing()

answered Sep 6, 2019 at 6:06

Pranoy Sarkar

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Comments

StackSlave · Accepted Answer · 2019-09-06 06:14:30Z

1

I would not make my structure like this, but perhaps you should take a look.

class WTF{
  constructor(clickElement){
    this.clickElement = clickElement; this.checkBool = false;
    clickElement.onclick = e => {
      this.click();
      console.log(this.checkBool);
    }
  }
  click(){
    this.checkBool = !this.checkBool;
    return this;
  }
}
let wtf = new WTF(document);

Just keep clicking on the page.

answered Sep 6, 2019 at 6:14

StackSlave

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saygin · Accepted Answer · 2019-09-06 06:08:33Z

0

you have typeo 1- start class with lowercase class 2- check eventlistener syntax

    class D {
  constructor() {
    this.checkBoolen = false;
  }

  checkBoolen = false // error, asks to install @babel/plugin-proposal-class-properties to get support.

  click() {
   document.addEventListener('click', (e) => {
      this.checkBoolen=true; // <- a class constructor's prototype property can't be reassigned.
   });
  }

  doSomthing() {
   if(this.checkBoolen = true ) {
    console.log('do something');
   }
  }
}

answered Sep 6, 2019 at 6:08

saygin

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