/

Understanding JavaScript Operators Precedence Rules

Understanding JavaScript Operators Precedence Rules

In JavaScript, when dealing with complex statements, understanding operator precedence is crucial. It determines the order in which operations are executed and can greatly impact the results.

Let’s take an example:

1
const a = 1 * 2 + 5 / 2 % 2;

The expected result is 2.5, but why? Which operations take precedence over others?

To answer these questions, we need to familiarize ourselves with the precedence rules. Here is a table that lists the precedence of various operators:

Operator Description
- + ++ -- Unary operators, increment, and decrement
* / % Multiply, divide, modulo
+ - Addition, subtraction
= += -= *= /= %= **= Assignments

Operators on the same level, such as addition and subtraction (+ and -), are executed in the order they appear.

Let’s apply these precedence rules to our calculation:

1
2
3
4
5
const a = 1 * 2 + 5 / 2 % 2;
const a = 2 + 5 / 2 % 2;
const a = 2 + 2.5 % 2;
const a = 2 + 0.5;
const a = 2.5;

By following the precedence rules, we determine that the final value of a is 2.5.

Understanding operator precedence is essential to write correct and predictable JavaScript code. By knowing which operations take precedence over others, you can avoid potential bugs and ensure accurate results.

tags: [“JavaScript”, “Operators Precedence”, “Calculation”, “Programming”]