(Using order of operations in JavaScript)
When writing arithmetic in JavaScript, operator precedence dictates the order in which operations are performed. For example, multiplication has a higher precedence than addition. This means that if an expression contains both multiplication and addition operators (such as the example below), the multiplication will be evaluated first.
(Example)
var x = 10 + 5 * 2;In the above example, what is the value of x?
Luckily, JavaScript uses the same operational order as traditional mathematics, which tells us that x = 20.
(Example)
var x = (10 + 5) * 2;When using parentheses, the operations inside are calculated first. In the above example, x = 30.
(Example)
var x = 10 + 5 - 2;
When operations have the same precedence (like addition and subtraction), they are calculated from left to right:
In the above example, x = 13.
Here is a basic list of operator precedence in JavaScript
| Order | Operator | Description | Example |
|---|---|---|---|
| 1 | ( ) | Expression grouping | (10 + 5) |
| 2 | * | Multiplication | 10 * 5 |
| 2 | / | Division | 10 / 5 |
| 2 | ** | Exponentiation | 10 ** 5 |
| 3 | + | Addition | 10+5 |
| 3 | - | Subtraction | 10-5 |