Operators

Operators in JS

• Arithmetic Operators
• Assignment Operators
• Comparison Operators
• Logical Operators
• Ternary Operators

Arithmetic Operators

console.log(10 + 5); // Addition -> 15
console.log(10 - 5); // Subtraction -> 5
console.log(10 / 2); // Division -> 5
console.log(10 * 4); // Multply -> 40
console.log(7 % 2); // Modulas -> 1
console.log(2 ** 4); // 16
console.log(2++); // Increment -> 3
console.log(2--); // Decrement -> 1

• Post and Pre Increment/Decrement

let x = 5;
// x++, it will increase the value of x when the program control goes to the next statement.
// ++x, it will increase the value of x there only

x++; //post-increment, x will be 5 here and 6 in the next line
++x; //pre-increment, x will be 7 here
x--; //post-decrement, x will be 7 here and 6 in the next line
--x; //pre-decrement, x will be 5 here

Assignment Operators

let x = 10 + 5; // Assigns right operand value to the left operand. -> 15
x += 10; // Sum left and right operand and stores in left operand -> 25
x *= 4; // Multiply left and right operand and stores in left operand -> 100
// [ " -= " for Subtraction , " /= " for Division , " %= " for Modulas ]
x++; // 101
x--; // 100
x--; // 99
console.log(x); // 99

Comparison Operators

console.log(40 == 8); // Compares the equality of two operands without considering type.
console.log(40 === 8); // Compares equality of two operands with type.
console.log(40 != 8); // Compares inequality of two operands without considering type.
console.log(40 !== 8); // Compares inequality of two operands with type.
console.log(40 < 8); // Less Than / return true if 40 <> 8
console.log(40 >= 8); // Greater Than equal to / return true if 40 >= 8
console.log(40 <= 8); // Less Than equal to / return true if 40 <>= 8

Logical Operators

let a = 5,
    b = 10;

a != b && a < b; // returns true. // Both Condition should true.
a > b || a == b; // returns false // One Condition should true
a < b || a == b; // returns true
!(a < b); // returns false // Inverse the Solution true <-> false
!(a > b); // returns true

Ternary Operators

The second part (after ? and before :) will be executed if the condition turns out to be true. Suppose, the condition returns false, then the third part (after :) will be executed.

let a = 10,
    b = 5;

var c = a > b ? a : b; // value of c would be 10
var d = a > b ? b : a; // value of d would be 5

Spread/Rest Operator

//  Unpacking Array at Once by spread Operator
const arr = [7, 8, 9];
const badNewArr = [1, 2, arr[0], arr[1], arr[2]]; // [1, 2, 7, 8, 9]

const newArr = [1, 2, ...arr]; // [1, 2, 7, 8, 9]
// spread operator is comma seprated Value -> It can be Used for all iterable ( string , array , map , sets ) But not Objects
// this are completing new array

console.log(newArr); // [1, 2, 7, 8, 9]
console.log(...newArr); // 1 2 7 8 9

// Spread operator on String
const str = 'Jonas';
const letters = [...str, '', 'S.']; // ['J', 'o', 'n', 'a', 's', '', 'S.']

// Spread operator are only Used when multiple Values can enter... like you can't use in tmeplte litral

// SPREAD, beacuse it is on RIGHT side of =   -> value seprated by commas
const arr = [1, 2, ...[3, 4]];
console.log(arr); // [1, 2, 3, 4]

// REST, beacuse on LEFT side of =   -> variable seprated by Comma
const [a, b, ...others] = [1, 2, 3, 4, 5, 6];
console.log(a, b, others); // 1 2 [3, 4, 5, 6]

const [pizza, resto, ...otherFood] = [
    ...restaurant.mainMenu,
    ...restaurant.starterMenu,
];
console.log(pizza, resto, otherFood); // Pizza Pasta ['Risotto', 'Focaccia', 'Bruschetta', 'Garlic Bread', 'Caprese Salad']

// Objects
const { sat, ...weekdays } = restaurant.openingHours;
console.log(sat, weekdays); // {open: 0, close: 24} {thu: {…}, fri: {…}}

// FUNCTIONS
const add = function (...numbers) {
    let sum = 0;
    for (let i = 0; i < numbers.length; i++) sum += numbers[i];
    console.log(sum);
};
add(2, 3);
add(2, 3, 4);
add(2, 3, 4, 5);
add(2, 4, 54, 45);

const x = [2, 5, 1, 51, 54, 54, 5];
add(...x);

// Copy Array
const myArr = [1, 2, 3];
const myCopy = [...myArr]; // All elemt of myArr will be Copied