Just like we have contracts in the legal world to tell us what we can and can't do, in the world of TypeScript these contracts are called interfaces. They are a way to define the contract or shape of an object. It is a type that describes the structure of an object and specifies what properties and methods the object must have. Interfaces help to enforce consistency and correctness in code.
Here's an example of an interface in TypeScript:
interface Dog { name: string; breed: string; age: number; bark: () => void;}This interface specifies that any object of type Dog must have a name property of type string, a breed property of type string, an age property of type string and a bark() method that takes no arguments and returns nothing.
To use an interface, you can declare an object that implements the interface like this:
const dog: Dog = { name: "Fido", breed: "Labradoodle", age: 3, bark: () => console.log("Bow wow!")}This object dog is of type Dog, because it has all the properties and methods specified in the Dog interface. If you try to create an object that doesn't match the interface, TypeScript will give you an error.