JavaScript Operator Precedence

Understanding operator precedence is essential for writing accurate and efficient JavaScript code. Operator precedence determines the order in which operators are evaluated in an expression.

Operator Precedence Values

Operators with higher precedence are evaluated before those with lower precedence.

Example:

let result = 3 + 5 * 2; // Multiplication (*) is evaluated before addition (+) console.log(result); // 13

Increment Operators

++: Increases a variable’s value by 1.
–: Decreases a variable’s value by 1.

Example:

let a = 5; console.log(++a); // 6 console.log(a–); // 6 (then decrements to 5)

NOT Operators

!: Logical NOT operator, inverts the truth value.
~: Bitwise NOT operator.

Example:

console.log(!true); // false console.log(!false); // true

Unary Operators

Unary operators operate on a single operand.

+: Unary plus.
-: Unary minus.
typeof: Data type
Void: Evaluate void.
Delete: Property delete.

Example:

let x = 10; console.log(-x); // -10

Arithmetic Operators

Common arithmetic operators include:

+: Addition
-: Subtraction
*****: Multiplication
/: Division
%: Modulus (remainder)

Example:

console.log(10 + 5); // 15 console.log(10 % 3); // 1

Shift Operators

Shift operators manipulate the bits of numbers.

<<: Left shift
>>: Right shift(signed)
>>>: Right shift(unsigned)

Example:

console.log(5 << 1); // 10 console.log(5 >> 1); // 2

Relational Operators

Relational operators compare values.
in: Property in object.
instanceof: Instance of object.

Example:

console.log(5 > 3); // true console.log(5 <= 5); // true

Comparison Operators

Comparison operators include:

==: Equal to
===: Strict equal to
!=: Not equal to
!==: Strict not equal to
<: Less than.
<=: Less than or equal.
>: Greater than.
>=: Greater than equal.

Example:

console.log(5 == “5”); // true console.log(5 === “5”); // false

Bitwise Operators

Bitwise operators work on binary representations of numbers.

Example:

console.log(5 & 1); // 1 (AND) console.log(5 | 1); // 5 (OR)

Logical Operators

Logical operators include:

&&: AND
||: OR

Example:

console.log(true && false); // false console.log(true || false); // true

Conditional (Ternary) Operator

The ternary operator evaluates a condition and returns one of two values.

Example:

let age = 18; let message = age >= 18 ? “Adult” : “Minor”; console.log(message); // Adult

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JavaScript Operator Precedence