Data Types
Before going to start learning JavaScript you have to start
from the basics. Many of them are directly going to the main topics and faced
many stragles to learn any framework or Libraries after JavaScript. So here we
will explain you about the Data Types which are available in JavaScript. Because
in Interview you will be asked this kind of questions.
In JavaScript there are 2 different data types are there,
- Primitive Data Types
- Reference Data Types
Primitive Data Types
When you create any js code you may need to store any value
in a variable, inside that variable you can store any kind of data like
objects, array or other data types. There are some important data types are
available that be asked in interview of JavaScript or React, Angular or any
other framework jobs. Because without JavaScript those frameworks will not
work.
In JavaScript there are 7 types of primitive types, they are
- String
- Number
- Boolean
- Undefined
- Null
- BigInt
- Symbol
String
The string is just the characters whichever you typed in the
scripts. It can be number or alphabets. Everything which are inside the single,
double quotes or backticks are considers as strings. Most you will use any
quotes while writing a string in your scripts. But in sometimes you may need to
use single quote in your sentence, in that time you can combine both quotes.
Backticks: This is another useful method to write
strings inside your code, sometimes you may need to insert dynamics values
which are stored in different variables
Number
In most programming language you might hear Int or float for
numbers. In JavaScript both integer and float values are Number type only. You
can check the data type using some method which built in JavaScript they will
see that later because that are advanced topics for beginners.
Float: number which has decimal points
Boolean
Boolean is very important data type which you may need to
use in many places. In many conditions you might face some situation like yes
or no. In programming we called that True or False, you may know logical
operators already. If not don’t worry you will learn everything from here.
Mostly this will be useful in If conditions or Ternary operators.
Null
Null is nothing inside a variable, it means it is not
number, string, Boolean or any other data types it’s like a empty place. Mostly
this will be used at the initial stage and later may be changed the values for
some reasons.
Undefined
Usually, we will define some values in the Let, Const or var, but in sometimes you may just create a variable and did not store any data in that variable. But you can't create a variable without data in const that you may already know. Basically, whichever the variable which was not defined that is called undefined type.
We can manually set a variable to undefined but it is not
recommended way to store a data in a variable.
Symbol
Symbol type was introduced in ES6 (ECMA Script 2015). mostly
for beginners you may not use this. Also, in interviews also many of the
companies not asking about symbol but if you will be asked the data types. That
time if you explain about symbols your profile may get shortlisted because of
basic JavaScript knowledge were strong. Symbol is is built in object which
returns a unique symbol.
BigInt
This is used to store very big integer number, but mostly
you will no need to use this much big numbers in your projects.
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