Chapter VIII · Arrays
map
The map method transforms every item in an array by passing it through a callback function, returning a brand new array.
01 How It Works
Think of a factory processing line converting raw input materials into finished goods.
map iterates through each element, applies the transformation callback, and collects results into a new array.
example.js
const nums = [1, 2, 3];
const doubled = nums.map(n => n * 2); // [2, 4, 6]1. Call .map() on an input array.
2. Provide a transformation callback function.
3. Receive the newly mapped array output.
02 Practical Example
Here is how you might see this concept applied in real-world code:
practical.js
const names = ["alice", "bob"];
const caps = names.map(n => n.toUpperCase());Key Takeaway
Use map when you need to transform each element of an array into a new value.