There are two different ways in TypeScript how you can specify the structure of your data
We can use Interface and Types
They are very similar, almost everything you can do with the Interface, you can also do with the Type
In TypeScript is recommending to use Interface over Type alias when it's possible
Interface describes data structure in a more natural way
Interface keyword exists only in TypeScript non in vanilla JavaScript. It is helping us to write structured and very explicit code that can help you force classes to have certain features or objects in general to have a specific structure. They allow for optional properties and all optional methods if you add a question mark after the method name
You can't assign a default value inside the Interface, just the property's name, and type
interface User {
username: string
project: string
years: number
hello?(name: string): void
}
const userOne: User = {
username: "slavo3dev",
project: "NRG Nomad",
years: 1
}
Type Alias
type Username = string
type PersonLogFunction = (name: string) => string
const username: string = "Slavo3 NRG Nomad"
const logUser: PersonLogFunction = (name) => {
return name;
}
const firstUser: Username = logUser(username)
