Note_Tech

All technological notes.

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JavaScript - Operators

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• JavaScript - Operators
  • Arithmetic Operators
  • Assignment Operators
    • Logical Assignment Operators
  • Comparison Operators
  • Logical Operators
  • Type Operators
  • Bitwise Operators
  • Conditional (Ternary) Operator
  • The Nullish Coalescing Operator (??)
  • typeof Operator
  • delete Operator
  • The Spread Operator: ...
  • The in Operator
  • The instanceof Operator

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Arithmetic Operators

Operator	Description
+	Addition
-	Subtraction
*	Multiplication
**	Exponentiation (ES2016)
/	Division
%	Modulus (Division Remainder)
++	Increment
--	Decrement

• Operators and Operands

  • The numbers (in an arithmetic operation) are called operands.

  • The operation (to be performed between the two operands) is defined by an operator.

• Remainder

  • The modulus operator (%) returns the division remainder.
  • In arithmetic, the division of two integers produces a quotient and a remainder.
  • In mathematics, the result of a modulo operation is the remainder of an arithmetic division.

• Incrementing

  • The increment operator (++) increments numbers.

  let x = 5;
  x++;
  let z = x; //x=6
  

• Decrementing

  • The decrement operator (--) decrements numbers.

• Exponentiation

  • The exponentiation operator (**) raises the first operand to the power of the second operand.

• Precedence

  • Operator precedence describes the order in which operations are performed in an arithmetic expression.

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Assignment Operators

Operator	Example	Same As
=	x = y	x = y
+=	x += y	x = x + y
-=	x -= y	x = x - y
*=	x *= y	x = x * y
/=	x /= y	x = x / y
%=	x %= y	x = x % y
**=	x **= y	x = x ** y

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Logical Assignment Operators

Operator	Example	Same As
&&=	x &&= y	x = x && (x = y)
`		=`	x || = y	x = x || (x = y)
??=	x ??= y	x = x ?? (x = y)

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Comparison Operators

Operator	Description
==	equal to
===	Strict equality,equal value and equal type
!=	not equal
!==	not equal value or not equal type
>	greater than
<	less than
>=	greater than or equal to
<=	less than or equal to
?	ternary operator

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Logical Operators

Operator	Description
&&	logical and
`		`	logical or
!	logical not

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Type Operators

Operator	Description
typeof	Returns the type of a variable
instanceof	Returns true if an object is an instance of an object type

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Bitwise Operators

• Bit operators work on 32 bits numbers.

• Any numeric operand in the operation is converted into a 32 bit number. The result is converted back to a JavaScript number.

Operator	Description	Example	Same as	Result	Decimal
&	AND	5 & 1	0101 & 0001	0001	1
`	`	OR	5	1	0101	0001	0101	5
~	NOT	~ 5	~0101	1010	10
^	XOR	5 ^ 1	0101 ^ 0001	0100	4
<<	left shift	5 « 1	0101 « 1	1010	10
>>	right shift	5 » 1	0101 » 1	0010	2
>>>	unsigned right shift	5 »> 1	0101 »> 1	0010	2

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Conditional (Ternary) Operator

• The conditional operator assigns a value to a variable based on a condition.

• Syntax:

variablename = condition ? value1 : value2;

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The Nullish Coalescing Operator (??)

• The ?? operator returns the first argument if it is not nullish (null or undefined).

• Otherwise it returns the second argument.

• Syntax:
  • arg1 ?? arg2

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typeof Operator

• The typeof operator returns the type of a variable, object, function or expression.

Target	typeof
undefined	"undefined"
NaN	"number"
null	"object"
Array	"object"
Date	"object"

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delete Operator

• The delete operator deletes a property from an object from an object.

• The delete operator is designed to be used on object properties. It has no effect on variables or functions.

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The Spread Operator: ...

• The ... operator expands an iterable into more elements.
• The ... operator can be used to expand an iterable into more arguments for function calls.

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The in Operator

• The in operator returns true if a property is in an object, otherwise false.

console.log("\n-------- in Operator --------\n");

const person = { firstName: "John", lastName: "Doe", age: 50 };

console.log("firstName" in person); //true
console.log("age" in person); //true
console.log("address" in person); //false

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The instanceof Operator

• The instanceof operator returns true if an object is an instance of a specified object.

console.log("\n-------- instanceof Operator --------\n");

const cars = ["Saab", "Volvo", "BMW"];

console.log(cars instanceof Array); // true
console.log(cars instanceof Object); // true
console.log(cars instanceof String); // false
console.log(cars instanceof Number); // false

function Person(fname, lname) {
  this.firstName = fname;
  this.lastName = lname;
}

class Car {
  constructor(brand) {
    this.carname = brand;
  }
}

const p1 = new Person("John", "Doe");
const car = new Car("Ford");

console.log(p1 instanceof Person); //true
console.log(car instanceof Person); //false
console.log(car instanceof Car); //true
console.log(p1 instanceof Car); //false

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