JavaScript8 min read
JavaScript Function Parameters: Rest and Defaults
Master function parameters. Learn rest parameters, default values, and parameter destructuring.
Alex Thompson
December 19, 2025
0.0k0
JavaScript Function Parameters
Rest Parameters
Collect remaining arguments:
```javascript function sum(first, ...rest) { return first + rest.reduce((a, b) => a + b, 0); }
sum(1, 2, 3, 4); // 10 ```
Default Parameters
```javascript function greet(name = 'Guest') { return `Hello, ${name}`; } ```
Parameter Destructuring
```javascript function displayUser({ name, age }) { console.log(`${name} is ${age}`); }
displayUser({ name: 'John', age: 25 }); ```
Key Takeaway
Rest collects arguments. Defaults provide fallbacks. Destructuring extracts from objects. Powerful parameter features.
#JavaScript#Functions#Parameters#ES6#Intermediate