Typing Object Shapes

Objects are the backbone of JavaScript. Configs, props, API payloads—you name it, they’re everywhere. But here’s the problem: in JavaScript, object shapes are a free-for-all. We can pass anything, forget properties, or mistype keys, and the interpreter won’t blink until our app explodes at runtime.

TypeScript changes the game. With its object typing system, we stop relying on wishful thinking and start enforcing structure. Want to guarantee that every User has a name and an id, but bio is optional? TypeScript makes that rock solid. Want to ensure nobody ever overwrites your database-assigned IDs? You can make that possible.

Enforcing object shapes with literal types

Let’s start with the fundamentals. In TypeScript, we can declare object shapes right where we use them. These are called object literal types. They’re perfect when we want to be explicit and tight with our shape.