JS: first-class objects

When I come across new material, I frequently like to tell the same information to myself using different words. It just helps to understand it much better.

In the last weeks of CS169.2x class, discussion touched upon Javascript and first-class objects. Javascript functions are first-class object, which means that they can be passed as arguments to other functions, returned as values from other functions, be a part of a data structure or assigned as variables.

What does this look like? A simplified example based on the lectures/the book will look like this:

var Square = function(side){
    this.side = side;
    this.result = function(){
       return this.side * this.side;
    }
}

Square works as a constructor and creates a new object when we call it using the word new:

my_square = new Square(2);

We can then call the result function like this (keeping parenthesis is important):

my_square.result();

As such, this creates a new object whose properties are initialized in the constructor, and we then can return a value from the result function.

There is much more to this, of course. This is a short explanation based solely on my understanding of the CS169.2x materials up to date. Javascript is a huge, vast land, and I am looking forward to exploring its vastness and digging further into details.