JavaScript Symbol type: (non-string object keys)

Question

What is the "Symbol" javascript type as mentioned in this ECMAScript 6 draft specification?

To quote the spec:

The Symbol type is the se

Answer 1

We use symbols to make properties or methods of an object private. So we hide the details and show only the essentials. It is called abstraction.

How to implement this:Let's create a simple class with "radius" property

class Circle {
    constructor(radius) {
        this.radius = radius; 
    }
    }

A symbol is essentially a unique identifier. Every time we call this function we get a unique identifier. It is not a constructor function,though.

Symbol()===Symbol() //will be false

Implementation:

const _radius=Symbol()
class Circle {
    constructor(radius) {
    this[_radius] = radius; //since property name starts with _, we use bracket notation
        }
         }

now test this. Create an instance of Circle:

const c=new Circle;
console.log(Object.getOwnPropertyNames(c))// you will see a number on the console.