Learn What are Data-types? | Data Types and Variables

What are Data-types?

The values which we assign to the variables are of a specific type which is called the data type of that specific variable. We can assign numbers, string, boolean, null, undefined, array, object, functions, and symbols to variables.

Introduction to different Data-types

Following is a brief introduction to the commonly used data types in JavaScript. We will go through these in detail in the upcoming chapters, but for now, let’s just get a basic understanding of all these.

Number

Numbers are always floating-point numbers so both the integers as well as floating-point numbers are simply numbers in JavaScript.


              12
            
let totalCoins=100;
console.log(totalCoins)

BigInt: BigInt is used to represent numbers of arbitrary lengths. A BigInt number can be generated by appending n at the end of a number.


              123
            
// the "n" at the end means it's a BigInt
const bigInt = 12345678901234567890123n;
console.log(bigInt);

Strings:
We use quotes to represent the strings. They are commonly used to deal with text.


              12
            
let comment="good";
console.log(comment);

Boolean (logical type): In this type, we have only two values: true and false. We use true for “Yes”, and false is used for “No”. For instance, if we want to store the value of "It's raining" we will set the value to true and if it is not raining then we will set the value false.


              12
            
let isRaining = true;
console.log(isRaining);

null: The null is a special value that represents “nothing”, “empty”, or “value unknown”.


              12
            
let selectedColor = null;
console.log(selectedColor)

Undefined: In JavaScript, a default value of undefined is assigned to the variable if we do not assign a value to it.


              12
            
let age;
console.log(age);

The `typeof` Operator:

The typeof operator is used to get the type of the value or variable. It’s useful to quickly check the types of values that are assigned to the variable. To check the type we use the typeof keyword and pass the variable inside parentheses.


              12
            
let drink="soda";
console.log('typeof("drink"):', typeof(drink));

Task

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Check the type of the following variable and display it on the console.

Solution

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Section 3. Chapter 2

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What are Data-types?

Introduction to different Data-types

Number

Numbers are always floating-point numbers so both the integers as well as floating-point numbers are simply numbers in JavaScript.


              12
            
let totalCoins=100;
console.log(totalCoins)

BigInt: BigInt is used to represent numbers of arbitrary lengths. A BigInt number can be generated by appending n at the end of a number.


              123
            
// the "n" at the end means it's a BigInt
const bigInt = 12345678901234567890123n;
console.log(bigInt);

Strings:
We use quotes to represent the strings. They are commonly used to deal with text.


              12
            
let comment="good";
console.log(comment);

Boolean (logical type): In this type, we have only two values: true and false. We use true for “Yes”, and false is used for “No”. For instance, if we want to store the value of "It's raining" we will set the value to true and if it is not raining then we will set the value false.


              12
            
let isRaining = true;
console.log(isRaining);

null: The null is a special value that represents “nothing”, “empty”, or “value unknown”.


              12
            
let selectedColor = null;
console.log(selectedColor)

Undefined: In JavaScript, a default value of undefined is assigned to the variable if we do not assign a value to it.


              12
            
let age;
console.log(age);

The `typeof` Operator:


              12
            
let drink="soda";
console.log('typeof("drink"):', typeof(drink));

Task

Swipe to start coding

Check the type of the following variable and display it on the console.

Solution

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 3. Chapter 2

single

What are Data-types?

What are Data-types?

Introduction to different Data-types

The typeof Operator:

Solution

What are Data-types?

What are Data-types?

Introduction to different Data-types

The typeof Operator:

Solution

The `typeof` Operator:

The `typeof` Operator: