06_Operators.js

"use strict"; // using a variable without its previous declaration is treated as an error

/*---------------------------Assignment Operator----------------------------*/

const name = "Alice";
console.log(name); // -> Alice

let year = 2050;
let newYear = year = 2051; // If several assignment operators appear in a sequence, the order from right to left applies. 

/*---------------------------Arithmatic Operator---------------------------*/

const x = 5;
const y = 2;
 
console.log("addition: ", x + y); // -> 7
console.log("subtraction: ", x - y); // -> 3
console.log("multiplication: ", x * y); // -> 10
console.log("division: ", x / y); // -> 2.5
console.log("division remainder :", x % y); // -> 1
console.log("exponent: ", x ** y); // -> 25


/*------------------------------Unary arithmetic operators----------------------------*/

let str = "123";
let n1 = +str;
let n2 = -str;
let n3 = -n2;
let n4 = +"abcd";
 
console.log(`${str} : ${typeof str}`); // -> 123 : string
console.log(`${n1} : ${typeof n1}`); // -> 123 : number
console.log(`${n2} : ${typeof n2}`); // -> -123 : number
console.log(`${n3} : ${typeof n3}`); // -> 123 : number
console.log(`${n4} : ${typeof n4}`); // -> NaN : number


/*-----------------------------Unary increment and decrement operators--------------------------------*/

let n1 = 10;
let n2 = 10;

console.log(n1); // -> 10
console.log(n1++); // -> 10
console.log(n1); // -> 11

console.log(n2); // -> 10
console.log(++n2); // -> 11
console.log(n2); // -> 11

let n3 = 20;
let n4 = 20;

console.log(n3); // -> 20
console.log(n3--); // -> 20
console.log(n3); // -> 19

console.log(n4); // -> 20
console.log(--n4); // -> 19
console.log(n4); // -> 19

/*----------------------------------Compound Assignment Operators------------------------------------*/

let x = 10;
 
x += 2;
console.log(x); // -> 12
x -= 4;
console.log(x); // -> 8
x *= 3;
console.log(x); // -> 24
x /= 6;
console.log(x); // -> 4
x **= 3;
console.log(x); // -> 64
x %= 10;
console.log(x); // -> 4


/*-----------------------------------Logical operators----------------------------*/

// AND operator - &&
console.log(true && true); // -> true
console.log(true && false); // -> false
console.log(false && true); // -> false
console.log(false && false); // -> false

// OR operator - ||
console.log(true || true); // -> true
console.log(true || false); // -> true
console.log(false || true); // -> true
console.log(false || false); // -> false

// NOT operator - !
console.log(!true); // -> false
console.log(!false); // -> true


const a = false;
const b = true;
const c = false;
const d = true;
console.log(a && b && c || d); // -> true
console.log(a && b && (c || d)); // -> false


/*-----------------------------------Logical operators and non-Boolean values-----------------------------------*/

let nr = 0;
let year = 1970;
let name = "Alice";
let empty = "";
 
console.log(!nr); // -> true
console.log(!year); // -> false
console.log(!name); // -> false
console.log(!empty); // -> true
 
console.log(!!nr); // -> false (double negation is used to convert any type to Boolean.)
console.log(!!name); // -> true


console.log(true && 1991); // -> 1991
console.log(false && 1991); // -> false
console.log(2 && 5); // -> 5
console.log(0 && 5); // -> 0
console.log("Alice" && "Bob"); // -> Bob
console.log("" && "Bob"); // -> empty string
 
 
console.log(true || 1991); // -> true
console.log(false || 1991); // -> 1991
console.log(2 || 5); // -> 2
console.log(0 || 5); // -> 5
console.log("Alice" || "Bob"); // -> Alice
console.log("" || "Bob"); // -> Bob


let x = 0;
let y = 0;
console.log(x++ && y++); // -> 0
console.log(x); // -> 1
console.log(y); // -> y == 0


let a = true;
console.log(a); // -> true
a &&= false;
console.log(a); // -> false
let b = false;
console.log(b); // -> false
b ||= true;
console.log(b); // -> true