Data Types at a Glance
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In JavaScript we have 7 types of data:
Number , String , Boolean , Null , Undefined , Object , Symbol
Number: 1 , 2 , 3 , 100 , 3.14
String: 'hello , world' "[email protected]"
Boolean: true / false
They are a special logical true or false value.
We use this for evaluating conditions.
Null: Explicitly set a variable with no value.
This is a way where we can explicitly say the variable has no value.
So we could create a variable , but set it equal to null , to say that , that variable does not have,
a real value yet.
It is closely related to undefined , but the difrence is that undefined is a type that is given to variables
automatically by the browser that have not yet been defined.
"Null" and "Undefined" are both empty values , but "Null" we explicitly set to a variable and "Undefined" is
automatically given to a variable when are not yet defined.
Undefined: For variables that have not yet been defined.
Object: Complex data structures - Arrays , Dates , Literals etc.
These are more complex data structures , which can have multiple properties and functions , meaning
they can perform various diffrent things.
Now a lot of JavaScript is based using objects , and they are very many diffrent object types , or should we say
types of objects build into the language which we can use out of the box.
You might here the saying "everything in JavaScript is an object" which is an oversimplification , but it stems from a
source of truth.
Symbols: Used with objects.
They are a new addition to the JavaScript language , which are closely linked to objects.
Sumarization: A variable can hold any data type.We dont have to explicitly say what type of variable it will store , or
what type of data it will store.And we can overwrite a variable with a diffrent type too , meaning if we make a variable and
store a string in it , we can overwrite it later on(if we use "let" :-) ) with a number for example.
