Operator

Basic operators

Sample code:

var a = 10,
  b = 20;

// Addition
console.log(30 === a + b);
// Subtraction
console.log(-10 === a - b);
// Multiplication
console.log(200 === a * b);
// Division
console.log(0.5 === a / b);
// Complementation
console.log(10 === a % b);

Addition + can also be used to concatenate strings.

var a = ".w",
  b = "xs";

// String concatenation
console.log(".wxs" === a + b);

Unary operators

Sample code:

var a = 10,
  b = 20;

// Auto increment
console.log(10 === a++);
console.log(12 === ++a);
// Auto decrement
console.log(12 === a--);
console.log(10 === --a);
// Positive value
console.log(10 === +a);
// Negative value
console.log(0 - 10 === -a);
// Not
console.log(-11 === ~a);
// Negate
console.log(false === !a);
// Delete
console.log(true === delete a.fake);
// Void
console.log(undefined === void a);
// Typeof
console.log("number" === typeof a);

Bitwise operators**

Sample code:

var a = 10,
  b = 20;

// Left shift
console.log(80 === a << 3);
// Unsigned right shift
console.log(2 === a >> 2);
// Signed right shift
console.log(2 === a >>> 2);
// AND
console.log(2 === (a & 3));
// XOR
console.log(9 === (a ^ 3));
// OR
console.log(11 === (a | 3));

Comparison operators**

Sample code:

var a = 10,
  b = 20;

// Less than
console.log(true === a < b);
// Greater than
console.log(false === a > b);
// Less than or equal to
console.log(true === a <= b);
// Greater than or equal to
console.log(false === a >= b);

Equality operator**

Sample code:

var a = 10,
  b = 20;

// Equal sign
console.log(false === (a == b));
// Not equal sign
console.log(true === (a != b));
// Equivalent sign
console.log(false === (a === b));
// Not equivalent sign
console.log(true === (a !== b));

assignment operator**

Sample code:

var a = 10;

a = 10;
a *= 10;
console.log(100 === a);
a = 10;
a /= 5;
console.log(2 === a);
a = 10;
a %= 7;
console.log(3 === a);
a = 10;
a += 5;
console.log(15 === a);
a = 10;
a -= 11;
console.log(-1 === a);
a = 10;
a <<= 10;
console.log(10240 === a);
a = 10;
a >>= 2;
console.log(2 === a);
a = 10;
a >>>= 2;
console.log(2 === a);
a = 10;
a &= 3;
console.log(2 === a);
a = 10;
a ^= 3;
console.log(9 === a);
a = 10;
a |= 3;
console.log(11 === a);

binary logical operator**

Sample code:

var a = 10,
  b = 20;

// Logical AND
console.log(20 === (a && b));
// Logical OR
console.log(10 === (a || b));

other operators**

Sample code:

var a = 10,
  b = 20;

//Conditional operator
console.log(20 === (a >= 10 ? a + 10 : b + 10));
//Comma operator
console.log(20 === (a, b));

Operator precedence

Priority	Operator	Description	Associativity
20	( ... )	parentheses	n/a
19	... . ...	member access	From left to right
19	... [ ... ]	member access	From left to right
19	... ( ... )	function call	From left to right
17	... ++	post-increment	n/a
17	... --	post-decrement	n/a
16	! ...	logical not	From right to left
16	~ ...	bitwise not	From right to left
16	+ ...	unary addition	From right to left
16	- ...	unary subtraction	From right to left
16	++ ...	pre-increment	From right to left
16	-- ...	pre-decrement	From right to left
16	typeof ...	typeof	From right to left
16	void ...	void	From right to left
16	delete ...	delete	From right to left
14	... * ...	multiplication	From left to right
14	... / ...	division	From left to right
14	... % ...	modulo	From left to right
13	... + ...	addition	From left to right
13	... - ...	Subtraction	From left to right
12	... << ...	Bitwise left shift	From left to right
12	... >> ...	Bitwise right shift	From left to right
12	... < ...	Unsigned right shift	From left to right
11	... >>> ...	Less than	From left to right
11	... <= ...	Less than or equal to	From left to right
11	... > ...	Greater than	From left to right
11	... >= ...	Greater than or equal to	From left to right
10	... == ...	Equal to	From left to right
10	... != ...	Not equal to	From left to right
10	... === ...	Exactly equal to	From left to right
10	... !== ...	Not exactly equal to	From left to right
9	... & ...	Bitwise AND	From left to right
8	.. ^ ...	Bitwise XOR	From left to right
7	... ｜ ...	Bitwise OR	From left to right
6	... && ...	logical and	From left to right
5	... ｜｜ ...	logical or	From left to right
4	... ? ... : ...	Conditional operator	From right to left
3	... = ...	Assignment	From right to left
3	... += ...	Assignment	From right to left
3	... -= ...	Assignment	From right to left
3	... *= ...	Assignment	From right to left
3	... /= ...	Assignment	From right to left
3	... %= ...	Assignment	From right to left
3	... <<= ...	Assignment	From right to left
3	... >>= ...	Assignment	From right to left
3	... >>>= ...	Assignment	From right to left
3	... &= ...	Assignment	From right to left
3	... ^= ...	Assignment	From right to left
3	... ｜= ...	Assignment	From right to left
0	... , ...	Comma	From left to right