JavaScript - Numbers

console.clear();

var num1 = 10; // Integer
var num2 = 10.9; // Decimal

console.log(typeof(num1));
console.log(typeof(num2));

// Addition
var num3 = 15;
var sum = num3 + num1 + num2;
console.log(sum);

// Substraction
var diff = num3 - num1;
console.log(diff);

// Multiplication
var mul = num3 * num1;
console.log(mul);

// Division
var div = num3 / num1;
console.log(div);

var divByZero = num3 / 0;
console.log(divByZero);
console.log(typeof(divByZero));

// Multiply by string
var mulByString = num3 * 'A';
console.log(mulByString);
console.log(typeof(mulByString));            
        

JavaScript - Number Functions

console.clear();

var num1 = 10;
var num2 = 20.3;

// toString() number as input and returns a string
console.log(num1.toString());
console.log(num2.toString());

var strNum1 = "100";
var strNum2 = "11.5";
var strNum3 = "ABC";

// parseInt() string numeral as input and returns a number
console.log(parseInt(strNum1));
console.log(parseInt(strNum2));
console.log(parseInt(strNum3));

// parseFloat() string numeral as input and returns a floating number
console.log(parseFloat(strNum2));
console.log(parseFloat(strNum3));

// toFixed() take a floating number and rounds it off to given position
var float1 = 87.987653;
console.log(float1.toFixed());
console.log(float1.toFixed(2));
console.log(float1.toFixed(5));                 
        

JavaScript - Strings

console.clear();

var myFirstString = "I love JavaScript";
console.log(typeof(myFirstString));

var mySecondString = 'We will learn JavaScript together';
console.log(typeof(mySecondString));

// What if my string contains a double quote
var doubleQuotesString = "This is a \"JavaScript\" string";
console.log(doubleQuotesString);

// What if my string contains a single quote
var singleQuotesString = 'This is a \'JavaScript\' string';
console.log(singleQuotesString);

var doubleQuotesString2 = "This is a 'JavaScript' string";
var singleQuotesString2 = 'This is a "JavaScript" string';
console.log(doubleQuotesString2);
console.log(singleQuotesString2);            
        

JavaScript - String Functions

console.clear();

var myFirstString = "This is a string for JavaScript string functions, JavaScript";

// Returns the length of a string
console.log(myFirstString.length);

// Find index of a string inside another string
console.log(myFirstString.indexOf('JavaScript'));
console.log(myFirstString.indexOf('This'));

// Find last index of a string indise another string
console.log(myFirstString.lastIndexOf('JavaScript'));
console.log(myFirstString.lastIndexOf('This'));

// Get a part of our string: slice(start, end)
console.log(myFirstString.slice(0, 5));
console.log(myFirstString.slice(21, 31));
console.log(myFirstString.slice(-10));
console.log(myFirstString.slice(5));

// Get sub string function: substr(start, length)
console.log(myFirstString.substr(0, 4));
console.log(myFirstString.substr(21, 10));
console.log(myFirstString.substr(21));          
        

JavaScript - String Functions 2

console.clear();

var exampleString = "This is JavaScript tutorial";

// toUpperCase() - converts string to upper case characters
console.log(exampleString.toUpperCase());

// toLowerCase() - converts string to lower case characters
console.log(exampleString.toLowerCase());

// concat() - merges two or more strings
var firstName = "JavaScript";
var lastName = "Playground";
console.log(exampleString.concat(firstName));
console.log(exampleString.concat(' ', firstName, ' ', lastName));

// We can also use '+' operator to concat two or more strings
console.log(firstName + ' ' + lastName + ' ' + exampleString);

// trim() - remove extra spaces
var extraSpaceString = "      mystring.   ";
console.log(extraSpaceString.trim());

var extraSpaceString2 = "      my string.   ";
console.log(extraSpaceString2.trim());

// charAt() - take a position as an argument and returns the character at that position
var charAtExampleString = "This is my test string";
console.log(charAtExampleString.charAt(5));
console.log(charAtExampleString.charAt(11));

// split() - splits a string on the basis of the arguments passed
var sampleString = "This is my sample string";
console.log(sampleString.split(' '));
console.log(sampleString.split('is'));

var sampleString2 = "This,is,my,sample,string";
console.log(sampleString2.split(','));

var sampleString3 = "This is awesome";
console.log(sampleString3.split());        
        

JavaScript - Null and Undefined Values

console.clear();

var mVar; // mVar holds no value
console.log(mVar);

mVar = null; // mVar holds the value null
console.log(mVar);