javascript primitive data types code example

Example 1: 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

Example 2: primitive and non primitive data types in javascript

//primitive = {STRING, NUMBER, BOOLEAN, SYMBBOL, UNDEFIEND, NULL}
//non-primitive = {ARRAY, OBJECT, FUNCTION}

//primitive is always copied by VALUE
var a = 1;
var b = a;
    //console.log(a , b) =  1 , 1
a = 3;
console.log(a) //3
console.log(b) // still 1 and not 3   (always copied by value only)


//non-primitive is always copied by REFERENCE
var x = {name : "Jscript"};
var y = x;
  //console.log(x , y)     TWICE =  Object { name: "Jscript" }
x.name = "Js";
console.log(x) //Js
console.log(y) //Js  {copied by reference} like pointers in C lang

Example 3: data types in javascript

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

Example 4: primitive and non primitive data types in javascript

Primitve vs Non Primitive