Data Types

A variable in JavaScript can contain any data.
It is possible to assign a string to a variable initially and then reassign the variable to a number.
A programming language that has this capability is called 'Dynamically Typed'


Value / Primitive TypesAre Immutablecannot be changed once they have been created
 string 
 number(float) Prone to rounding errors
 bigint 
 boolean 
 symbolAdded in ES 2015
 null 
 undefined 
Reference TypesAre Mutablecan be changed once it has been created
 object 
 function 


function Data Type

A 'function' data type is a special type of object.

typeof function() {} // "function" 
typeof new Function // "function"


array Data Type

An 'array' data type is a special type of object.
It does have some additional properties and functions that a normal object does not have.

typeof myArray            // "object" 

Arrays


null evaluates to False in a boolean expression
undefined evaluates to False in a boolean expression
primitive data types are equal if the values match




© 2022 Better Solutions Limited. All Rights Reserved. © 2022 Better Solutions Limited TopPrevNext