Data types in JavaScript: Difference between ‘==’ and ‘===’ in Javascript:

 Data types in JavaScript:

Data types are nothing but different types of data that can be stored. JavaScript provides two types of data types: Primitive and Non-primitive.

It is important to note that JavaScript is a dynamically typed language. It means that we do not have to specify the data type for a variable, it is done dynamically by the JavaScript engine.

 

1. Primitive Data Types:

Number: It represents numeric values, both with and without decimal.

Eg: let x = 5;

 

String: It represents a sequence of characters inside quotes. It can consist of letters, words, and sentences. It is important to note that even numbers enclosed inside quotes are treated as strings.

Eg: let x = "Test123";

 

Boolean: It represents either true or false.

Eg: let a = true;

 

Undefined: A variable that has not been assigned a value is of type undefined.

Eg: let a;

 

null: It represents null, which means no value at all.

Eg: let a = null;

 

2. Non-primitive data types:

 

Object: It represents information in the form of key-value pairs.

Example:

In the above example, city, state, and country are properties of the details object. They can be accessed either using the square bracket syntax as shown above i.e. details['city'] or they can be accessed using the dot syntax i.e. details.City

 

Array: It is used to store multiple values at once.

Example:

You will learn more about arrays and objects later on in the module.


  • Difference between ‘==’ and ‘===’ in Javascript:  You would have normally observed ‘==’ sign in if conditions. However, JS offers two types of equality checks, ‘===’ being the other option. What is the difference between both?
    • ‘==’ is called an equality operator and ‘===’ is a strict equality operator. As the name suggests, ‘===’ operator strictly checks the type as well while comparing two things while ‘==’ does not. 
    • ‘==’ actually converts the two operands into the same type and then compares the values. On the other hand, ‘===’ checks both type and values without any kind of conversion. 

Example:

It can be observed in the above example that when values of ‘a’ and ‘b; are checked without strict checking, the condition is true even when ‘a’ is a boolean and ‘b’ number. However, they are converted into a single type and checked.

This is because in JavaScript, 1 number is considered to be similar to a true boolean, and 0 number is considered to be similar to a false boolean.

On the other hand, ‘===’ sign offers strict checking where both types and values equality is checked. Hence, the condition fails since both ‘a’ and ‘b’ are of different types.

To avoid confusion, it is always recommended to use the strict equality operator, i.e. ===

Comments

Post a Comment

Popular posts from this blog

Day 9: CSS - Font Formate

Image
p1{  font style: italic, } p2{ font-variant: small-caps; } p3{ font-weight: 400px: } p4{ font-size: 12pt } p5{ font-family:  } ----------------------------------------------------------------------------------------------------------------------- The CSS font-family Property : The font-family property in CSS is used to specify the typeface of a text.      If the font name has more than one word, such as "Times New Roman," quotation marks must be used.        Example: The following code applies a font family to a paragraph using class ids:I        Code :   Output :     The CSS font-size Property : The font-size attribute controls a font's size.      It has an impact on the text size of an element. Every element can use it, and its default value is medium. This attribute has values like xx-small, small, x-small, etc.      Font-size can also be specified in pixels (which sets the f...
Read more

else-if condition in if-else statements: Concatenation in JavaScript :

Image
  else-if condition in if-else statements: While specifying conditions for if-else statements, there may arise a need to include more than just two scenarios. For example, suppose we have a variable ‘n’ and we have to check if it is positive or negative. JS code for this problem would look like this: Quite simple, right? However, suppose we twist this problem a bit. If we have to check if the value of ‘n’ is positive, negative, OR zero. Can we do it using only if-else?  No, right? Here comes the scenario where we have to check more than two conditions and give output for each. This is where else-if comes into the game.  Structure of if else-if else looks something like this: If (condition 1)  { statements } else if (condition 2) { statements } else  { statements }   Working for the above code is explained as follows: Condition 1 is checked first. If it is true, statements inside the first block are executed and the remaining conditions are not checked. If t...
Read more

Day 27: Css Variable

Image
 :root {   --main-color: #3498db; } .element {   background-color: var(--main-color); } HTML Code: <!DOCTYPE html> <html lang="en"> <head>   <meta charset="UTF-8">   <meta name="viewport" content="width=device-width, initial-scale=1.0">   <link rel="stylesheet" href="styles.css">   <title>Sample Page</title> </head> <body>   <div class="element">     This is a sample element with the specified background color.   </div> </body> </html> CSS Code: :root {   --main-color: #3498db; } .element {   background-color: var(--main-color);   padding: 20px;   color: white; /* Text color to make it visible on the background */ }
Read more