TSTypeScriptBeginnerEditable example10 min

Interfaces And Types

Interfaces And Types in practical TypeScript programs, with editable notebook code and a focused exercise.

Lesson notes

This lesson turns interfaces and types into a small example you can edit, copy and run locally.

typesinterfacessafer APIs

Editable notebook cell

Starter code

type User = {
  id: number;
  name: string;
};

const user: User = { id: 1, name: "Ada" };
console.log(user.name);

Output

Editable example

Run the code to see output here.

Try this

Change the sample data, predict the output and note what concept changed.

Hint: Make the smallest possible edit first.