Variables and Datatypes In JavaScript-series-1b

Santhi Sri Jamisetty — Sat, 08 Aug 2020 15:02:14 +0000

JavaScript is loose typed which means you don't need to specify the type of variable while declaring it, which differentiates other languages like Java, C++ wherein you need to specify its type while declaring a variable.
Ex: In JavaScript var age = 10;
In Java

int age = 10; specify the type of variable.

The Primitive Type datatype includes :

1)String ex: var color = "orange";
2)Number ex: var salary = 100;
3)Boolean(to check true or false) ex: isCatSleeping = true;
4)Null ex:refer to series 1a where in the table you see the "Registration Cost " for Andy Young has no value.
5)Undefined ex: var myCar; the variable myCar declared but has not set any value.
6)BigInt(recently added). These are for micro-precision timestamps.Please refer to MDN JavaScript for further reading.

Note:To check the variable dataype use this function called typeof();
Ex: var color = "orange"; typeof(color) output is "string".

The other called complex/composite datatypes because these include Objects as well as the Primitive types.
Objects includes Array
Array
Function etc.
We will learn about object-oriented programming later.

Modern browsers use ECMASCRIPT to overcome the scope of the variables. We will learn about it in series 1c. where we learn about hoisting, let, const etc.

Variables and Datatypes In JavaScript-series-1a

Santhi Sri Jamisetty — Thu, 06 Aug 2020 00:22:37 +0000

Photo by Maureen Sgro on Unsplash

What are variables? Why do we need them in programming.

Variables are containers (a memory location)as seen above in the color palette to store values and access them whenever required.

So what type of values our variables store?

Any value or any piece of information our containers can store. As in the color-palette which can store any color and remove the color, similarly, in variables we can rewrite the values as per the requirement.

Again the information stored in variable can be of same type, called "Primitive type" as in example 1 which stored a string.We'll get it to later when we learn about the data types.
Or the other type includes collections called "Objects" which hold different types together. Like when you work with excel file or database table the entire record or row is a collection which constitute numbers, null values, string etc. as in example 2

var myName = "Santhi"; ------example 1-Primitive type

First Name	Last Name	Registration Cost
Sean	Forbes	$1600
Jack	Rogers	$985
Andy	Young

          ...To be continued in series 1b.

DEV Community: Santhi Sri Jamisetty

Variables and Datatypes In JavaScript-series-1b

Variables and Datatypes In JavaScript-series-1a