To learn JavaScript, we must learn the basics.

In this article, we’ll look at the most basic parts of the JavaScript language.

Constructor Methods

We can add methods to constructors or classes.

For example, we can write:

class Plan {
  constructor(name, price, space, pages) {
    this.name = name;
    this.price = price;
    this.space = space;
    this.pages = pages;
  }
  calcAnnualPrice() {
    return this.price * 12;
  }
}

We add the calcAnnualPrice method to return the value of this.price * 12 .

this is the class instance, which is the object that’s created and returned when we invoke the Plan class.

So we get the price property from the object we create from the class and multiply it by 12.

To invoke the constructor and call the method on the created object, we can write:

const plan = new Plan('basic', 3, 100, 10)
console.log(plan.calcAnnualPrice())

We invoke the Plan constructor with the new keyword.

Then we call calcAnnualPrice on the plan object to get the annual price.

The class syntax is just syntactic sugar on top of prototype inheritance.

The calcAnnualPrice method is just a property of the Plan ‘s prototype property.

The prototype is the prototype of the Plan class, which is the object that it inherits from.

If we log the value of Plan.prototype.calcAnnualPrice :

console.log(Plan.prototype.calcAnnualPrice)

we see the code of the calcAnnualPrice method logged.

#javascript #technology #programming