?? JavaScript Operator Precedence

Operator precedence determines the order in which operators are evaluated in expressions. Operators with higher precedence execute before those with lower precedence.

Why It Matters

For example:

let result = 3 + 4 * 5;

• Multiplication (*) has higher precedence than addition (+), so

• 4 * 5 = 20 happens first, then 3 + 20 = 23.

• If you want addition first, use parentheses: (3 + 4) * 5 = 35.

Common Operator Precedence (High to Low)

Associativity

• Most operators are left-to-right associative (evaluated from left to right).

• Some, like exponentiation ** and assignment =, are right-to-left associative.

Example:

let x = 3 ** 2 ** 2; // Evaluated as 3 ** (2 ** 2) = 3 ** 4 = 81

Example Expression with Explanation

let result = 5 + 10 * 2 / (3 - 1);

Step-by-step:

1. (3 - 1) ? 2

2. 10 * 2 ? 20

3. 20 / 2 ? 10

4. 5 + 10 ? 15

Final result = 15

Use Parentheses to Avoid Confusion

Always use parentheses () to clarify evaluation order and improve code readability.

If you'd like, I can provide a complete precedence table or help you understand a complex expression!