JAVASCRIPT

js data types

true, false						// 1. Boolean
null 							// 2. Null
undefined 						// 3. Undefined
1, 4, 7, 231, 51, 11, 9			// 4. Number
9007199254740991n				// 5. BigInt
'Hello', 'World', 'Uzbekistan'	// 6. String
let sym1 = Symbol()				// 7. Symbol
{a: 123}, [1]					// 8. Objects

data type javascript

var age = 18;                           // number 
var name = "Jane";                      // string
var name = {first:"Jane", last:"Doe"};  // object
var truth = false;                      // boolean
var sheets = ["HTML","CSS","JS"];       // array
var a; typeof a;                        // undefined
var a = null;                           // value null

JavaScript Data Types?

Number  // var age = 18
String	// var name = "codepadding"
Boolean	// var prgramming = true
Object	// var fullName = {first:"Code", last:"Padding"};
Undefined // var program; typeof program
array	// var language = ["javaScaript","dart"]
null	// var error = null

javascript data types

/*JavaScript data types*/
//string
var string = 'ASCII text';
//int
var integer = 123456789;
//float
var float = 123.456;
//boolean, can be true or false
var t = true;
var f = false;
//undefined
var undef;//defaults to undefined
var undef = undefined;//not common, use null
//null
var nul = null;
//array
var arr = ['Hello','my','name','is','Dr.Hippo',123,null];
//object
var person = {'name':'John Smith','age':27};
//function
var fun = function(){
    return 42;
}

data types in javascript

//String Data Type
var strSingle = 'John'; //String with single quotes
var strDouble = "Bob"; //String with double quotes

//Number Data Type
var num = 25; //Integer
var flo = 80.5; //Floating-point number
var exp = 4.25e+6; //Exponential notation, this equates to 4250000

//Boolean Data Type
var isReading = true; //Yes, I'm reading
var isSleeping = false; //No, I'm not sleeping

//Undefined Data Type
var undef; //If a value is never assigned, any output will be 'undefined'

//Null Data Type
var noValue = null; //Null meaning that it is has no value, not the same as 0 or ""

//Object Data Type
var emptyObject = {};
var person = {"name": "Clark", "surname": "Kent", "age": "36"}; //The quotes around the propety name can be omitted if the property name is a valid JS name
var car = { //Same as person but easier to read
	model: "BMW X3", //Example with quotes around property name ommitted
	color: "white",
	doors: 5
}

//Array Data Type
var emptyArray = []; //An array can be of any data types (string, number, boolean, etc.)
var array = ["One", "Two"] //String array, note the index of the first element is 0

//Function Data Type
var func = function() { //Calling the function: func();
  alert("Code excuted"); //Outputs: Code executed
}

var funcVar = function(amount) { //Calling the function: funcVar(6); 
  alert("Code excuted " + amount + " times"); //Outputs: Code executed 6 times (if input was 6)
}

//Typeof Operator
typeof variable; //Returns the data type of the variable

What are JavaScript Data Types?

// What are JavaScript Data Types?
let name = "Chetan";                           // string
let age = 30;                                  // number 
let fullName = {first:"Chetan", last:"Nada"};  // object
let truth = false;                             // boolean
let language = ["HTML","CSS","JS"];            // array
let x; typeof x;                               // undefined
let val = null;                                // value null

javascript data types

var age = 18;                           // number 
var name = "Jane";                      // string
var name = {first:"Jane", last:"Doe"};  // object
var truth = false;                      // boolean
var sheets = ["HTML","CSS","JS"];       // array
var a; typeof a;                        // undefined
var a = null;                           // value null

javascript data types

/*
  Data Types Intro
  - String
  - Number
  - Array => Object
  - Object
  - Boolean
*/

console.log("Osama Mohamed");
console.log(typeof "Osama Mohamed");
console.log(typeof 5000);
console.log(typeof 5000.99);
console.log(typeof [10, 15, 17]);
console.log(typeof { name: "Osama", age: 17, country: "Eg" });
console.log(typeof true);
console.log(typeof false);
console.log(typeof undefined);
console.log(typeof null);

js data types

//There are 7 data types in JS 
//They're split in two categories - (Primitives and Complex Types)

//Primives
string, number, boolean, null, undefined

//Complex types
Object, Function

data types in js

typeof "John Doe" // Returns "string"
typeof 3.14 // Returns "number"
typeof true // Returns "boolean"
typeof 234567890123456789012345678901234567890n // Returns bigint
typeof undefined // Returns "undefined"
typeof null // Returns "object" (kind of a bug in JavaScript)
typeof Symbol('symbol') // Returns Symbol

JavaScript Data Types

let x = "16" + "Volvo";

js data types

let age = 16;                           // number 
let name = "John";                      // string
let name = {first:"Jane", last:"Duo"};  // object
let truth = false;                      // boolean
let sheets = ["HTML","CSS","JS"];       // array
let a; typeof a;                        // undefined
let a = null;                           // null

data types in javascript

1, 1.0 // Number
'String', "String"
true, false // Boolean
{id: 1;} // Object
[1, 2, 3] // Array

data types in javascript

// Data types in JavaScript
// In JavaScript, there are seven fundamental data types:
// first 6 is primitive data types (string, number, boolean, null, undefined, Symbol) and last one is complex data types (Object).

// Number: Any number, including numbers with decimals: 4, 8, 1516, 23.42.
let num = 23;
let num1 = 1.4;

// String: Any grouping of characters on your keyboard (letters, numbers, spaces, symbols, etc.) surrounded by single quotes: ' ... ' or double quotes " ... ", though we prefer single quotes. Some people like to think of string as a fancy word for text.
let name = 'chetan';
let name1 = 'ujesh';

// Boolean: This data type only has two possible values— either true or false (without quotes). It’s helpful to think of booleans as on and off switches or as the answers to a “yes” or “no” question.
let value = true;
let value1 = false;

// Null: This data type represents the intentional absence of a value, and is represented by the keyword null (without quotes).
let ans = null;

// Undefined: This data type is denoted by the keyword undefined (without quotes). It also represents the absence of a value though it has a different use than null. undefined means that a given value does not exist.
let que;
let coding;

// Symbol: A Symbol is a unique and immutable primitive value and may be used as the key of an Object property.
let sym = Symbol();
let sym1 = Symbol('foo');

// Object: An object contains properties, defined as a key-value pair. A property key (name) is always a string, but the value can be any data type, like strings, numbers, booleans, or complex data types like arrays, function and other objects.

// Array
let myArr = ['My','Name','is','Chetan'];
// Object
let person = {'firsName':'Chetan', lastName:'Nada' 'age':32};
// Function
let myFunction = function(){
    return "Thanks for Reading Data types in JavaScript";
}

reference data types in javascript

reference