CODEWITHSUNDEEP
javascript
JS_noob
JS_noob

Reputation: 97

Javascript calling a function in a function not defined classes

I am calling a method and want to have that method get the value of the returned value of the second method, to be able to use the variable in an element.

I always was able to call a function by putting the function in the other function. It seems when using classes I am unable to achieve this.

Do I have to use a callback method of some sort. I am new to classes.

class Bills{

    constructor(amount,payment,duedate,apr){
        this.amount = amount;
        this.payment = payment;
        this.duedate = duedate;
        this.total = total;
        this.apr = apr;

    }

  amountByMonth(billings){

//This is the function I am calling inside the function to get the value of.
      let dueDays = daysLeft(billings);

    const items = document.getElementById('bills');
    const newitem = document.createElement('ul');

    newitem.innerHTML = `
    <li>Monthly Amount Due :${billings.amount}</li>
    <li>Monthly Amount Due :${dueDays}</li>
    <li>Total On Card: ${billings.total}</li>`;


    items.appendChild(newitem);


  }

  daysLeft(billings){

let date1 = new Date();
let dueDate = new Date(billings.duedate);
let timeDiff = Math.abs(dueDate.getTime() - date1.getTime());
let diffDays = Math.ceil(timeDiff / (1000 * 3600 * 24)); 
console.log(diffDays);

return diffDays;

  }





}// end 




document.getElementById('subBtn').addEventListener('click',valueinput);

function valueinput(e){

 let amount = document.getElementById('payment').value;
 let total  = document.getElementById('total').value;
 let duedate = document.getElementById('dues').value;


  let billings = new Bills();

  billings.amount = amount;
  billings.duedate = duedate;
  billings.total = total;



  billings.daysLeft(billings);
  billings.amountByMonth(billings);

  e.preventDefault();
}

Upvotes: 0

Views: 872

Answers (2)

Esdras Xavier
Esdras Xavier

Reputation: 863

You must use this, for example if you want to call function inside the class function you must use this to your class knows the reference. So your code should looks like: 


  amountByMonth(billings){
     let dueDays = this.daysLeft(billings);

     // Rest of your code
  }

Upvotes: 0

Chris B.
Chris B.

Reputation: 5763

You need to make it clear that you are calling another method of the same class and not a different function by using this:

When you declare a class method without the function keyword, you're basically declaring it as a functional property of the class object. To refer back to the property, you need to put it in the context of the object it's defined in, i.e.

let dueDays = this.daysLeft(billings);

Upvotes: 1

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