"Objects and arrays are JavaScript's workhorses. Map and Set are their smarter siblings — built for the jobs where the workhorses struggle."
Introduction
JavaScript developers reach for objects and arrays instinctively — they're everywhere, they're familiar, and they handle most situations just fine. But both have real limitations that quietly cause bugs and unnecessary complexity.
What happens when you need an object whose keys aren't strings? What about storing a list of values where duplicates should be impossible? What if you need to know how many entries an object has without counting them yourself?
These are exactly the gaps that Map and Set were designed to fill. Introduced in ES6, they don't replace objects and arrays — they complement them. Knowing when to reach for each one is the mark of a developer who understands their tools.
