An object in JavaScript
Whenever we lower down vibration to identify with the intellect which is the inferior dimension of the mind, everything seems to be separated and definable. Anything can be defined by some properties and abilities. For example: A tree can be considered as an object which has name, age, and ability to produce.
To reflect this dimension of the mind into programming, the first programmers of the world decided to allow modeling objects in code. This makes programming more friendly and gives people more possibilities to turn their ideas into code. Let’s have a look at the example below.
JS code:
Here we have an object stored in the variable theTree. An object in JavaScript
is nothing but a bundle of variables and functions enclosed by a couple of
curly braces {}. In the example above, the variables name and age are used
to describe the tree’s properties; And the function produce is used to describe
its ability to yield fruits.
Please take note that we don’t need to use the keywords var and function for
bundled stuff of an object; Values are bound with the variables using colons :
instead of equal signs; And things are separated by commas ,
Normally, when referring to object, the variables are called properties and the
functions are called methods. But, it’s just the words matter, isn’t it? We’re
gonna keep calling them variables and functions because they’re just that.
To access the bundled variables and functions, a dot . is used to chain the
object’s reference and its bundled stuff. This is it! The dot which was mentioned
in our
first tutorial.
We’ve used it many times with the statement console.log(). The console itself
is an object; And the function log is actually bundled in the object.
Referring from the inside
In the section above, we’ve used the variable theTree to store the object’s
reference; Then access the bundled stuff of the object from outside by calling
the variable theTree. To use the object’s reference from the inside, the
keyword this is used to refer to the object itself.
JS code:
Creating object using class
Yet, creating object in JavaScript can be done in a more elegance way. Let’s check the code snippet below.
JS code:
The keyword class is used to create an object named Thing which serves as a
sketch. It does not have detail color and age; Instead, a constructor is
used to bind givenColor and givenAge when an actual object is created later.
And then we’ve created 2 objects using the keyword new, the sketch’s name, and
feeding detail color and age of each object. By creating objects this way, we
don’t have to write much repetitive code like variable names and the function
whisper which behave the same in the actual objects water and grass.
JavaScript also provides pre-defined classes and objects which give various conveniences. But, we’re gonna keep things simple now and save them for the next tutorials. Here is a small example which use a pre-defined class to get time information from system.
JS code:
Everything in JavaScript is Object
Not really. But, in fact, JavaScript treats almost everything as object. :D
A function is treated as an object. It’s a bundle.
JS code:
A number is also treated as an object. - Number Reference
JS code:
A string is treated as an object, too. - String Reference
JS code:
And we’ll meet more and more objects from now on. Our tutorial about object has
finished. In the next tutorial, we’ll meet a built-in object of web browser which
allows us to manipulate HTML document. Goodbye and see you next time in the realm
of intellect. :D
In case you wonder the realm beyond, here is an invitation to the superior
dimension of the mind, the dimension of knowing, where things are one, where
words and thoughts reach their limitation…
Invitation: