TypeScript Tips

Typing

When creating types it’s good to use interfaces instead of classes. Difference is that interface is not going to be transpiled to JavaScript, which results in a shorter JS code.

Example:

export interface IActivity {
    id: string;
    title: string;
    description: string;
    category: string;
    date: Date;
    city: string;
    venue: string;
}

Properties Declaration

We can quickly declare some class properties and make them settable via a constructor like this:

export class Ingredient {
  constructor(public name: string, public amount: number) {}
}

never type

There’s a never type. It’s a bit similar to void in the sense that the user is not expected to use the value of that type. The distintion is:

• functions that return void actually return undefined
• functions that return never are programmed in a way that they never actually return. They could always throw some exception or they might be just infinite.