Add Object to array with Class Syntax in JavaScript

Question

I want to pass an object to an array with the following Class and methods:

class PieData {
  constructor(data = [], name, y) {
    this.data = data;
    this.name = name;
    this.y = y;
  }
  addData() {
    this.data.push({
      name: this.name,
      y: this.y
    });
  }
}

const browsers = new PieData();

browsers.addData("Chrome", 25);
browsers.addData("Firefox", 30);

console.log(browsers);

The data should look like this:

let data = [
  {
 name: "Chrome",
 y: 61.41
   },
   {
 name: "Internet Explorer",
 y: 11.84
   }
]

Can anyone help me how to do this? This results in undefined :-(. I´m pretty new to programming. I think I do not really understand the "this" keyword.

You call browsers.addData("Chrome", 25); but that method doesn't take any parameters — VLAZ
– VLAZ, Commented Oct 28, 2019 at 19:19
Also, the constructor takes parameters but you never supply any. I find it hard to understand what the intent here is - is "Chrome" supposed to be the name put into the this.data array, or is it supposed to be the name of the object? Or something different? — VLAZ
– VLAZ, Commented Oct 28, 2019 at 19:21
The method should create an object like in the example data and be stored in the empty data array — Data Mastery
– Data Mastery, Commented Oct 28, 2019 at 19:24

Amós Assis · Accepted Answer · 2019-10-28 19:23:38Z

4

Instead to add values on constructor you must send the values into addData function

class PieData {
    constructor() {
        this.data = [];
    }
    addData(name, y) {
       this.data.push({ name, y });
    }
}

answered Oct 28, 2019 at 19:23

Amós Assis

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StepUp · Accepted Answer · 2019-10-28 19:25:57Z

1

Try to declare variable and use them in function:

class PieData {
    constructor(data = [], name, y) {
      this.data = data;
      this.name = name;
      this.y = y;
    }

    addData(name, y) {
        this.data.push({ name: name, y: y });
    }
 }



const browsers = new PieData([], 'test', 'y variable');

browsers.addData("Chrome", 25);
browsers.addData("Firefox", 30);

console.log(browsers);

answered Oct 28, 2019 at 19:25

StepUp

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