Rest and Spread
The spread operator ... expands iterables. The rest parameter collects remaining arguments into an array.
JavaScript
Beginner
4 min read
Rest and Spread
Example
function sum(...nums) { return nums.reduce((a, b) => a + b, 0); }
sum(1, 2, 3, 4); // 10
const arr1 = [1, 2]; const arr2 = [3, 4];
const merged = [...arr1, ...arr2]; // [1,2,3,4]
const obj = { a: 1 }; const clone = { ...obj, b: 2 }; // { a:1, b:2 }
Math.max(...[5, 3, 9]); // 9 Pro Tip
Spread creates a shallow copy — nested objects are still references.
Related Resources
JavaScript Reference
Complete tag & property list
JavaScript How-To Guides
Step-by-step practical guides
JavaScript Exercises
Practice what you've learned
More in JavaScript