Operator precedence in Javascript

Introduction

Operator precedence tells JavaScript which part of a math or logic problem to solve first. It helps avoid confusion and mistakes.

When you write math calculations with multiple operators like +, -, *, /

When you combine logic checks like &&, ||, and ! in one statement

When you want to understand how JavaScript reads your code without extra parentheses

When debugging why a calculation or condition gives an unexpected result

Syntax

Javascript

/* Example of operator precedence in JavaScript */
let result = 3 + 4 * 2;
// Multiplication (*) happens before addition (+)
console.log(result);

Operators like * and / have higher precedence than + and -.

Use parentheses () to change the order if needed.

Examples

Multiplication happens first: 3 * 2 = 6, then 5 + 6 = 11.

Javascript

let a = 5 + 3 * 2;
console.log(a);

Parentheses change order: 5 + 3 = 8, then 8 * 2 = 16.

Javascript

let b = (5 + 3) * 2;
console.log(b);

AND (&&) has higher precedence than OR (||), so false && false = false, then true || false = true.

Javascript

let c = true || false && false;
console.log(c);

NOT (!) has highest precedence: !false = true, then true && true = true.

Javascript

let d = !false && true;
console.log(d);

Sample Program

This program shows how operator precedence affects the results of calculations and logic expressions.

Javascript

let x = 10 + 5 * 2;
let y = (10 + 5) * 2;
let z = !false || false && true;

console.log('x =', x);
console.log('y =', y);
console.log('z =', z);

Important Notes

Remember: multiplication and division happen before addition and subtraction.

Logical NOT (!) happens before AND (&&), which happens before OR (||).

Use parentheses to make your code clear and control the order explicitly.

Summary

Operator precedence decides which operations run first in expressions.

Multiplication and division have higher precedence than addition and subtraction.

Use parentheses to change or clarify the order of operations.