Typescript Tutorial Development Tutorials, Guides & Insights

TypeScript provides several built-in utility types that make type manipulation easier. Some of the most commonly used utility types include Partial, Required, Pick, and Omit.

type PartialPoint = Partial<Point>; // All properties of Point are optional
type RequiredCircle = Required<Circle>; // All properties of Circle are required
type PointX = Pick<Point, 'x'>; // Only the 'x' property of Point
type CircleWithoutCenter = Omit<Circle, 'center'>; // All properties of Circle except 'center'

Interfaces in TypeScript define the shape of objects, providing a way to enforce structure:

interface User {
  id: number;
  name: string;
  email?: string; // Optional property
}

const user: User = {
  id: 1,
  name: "John Doe"
};

npm install --save-dev @types/jest

Add new tests to cover the type-specific logic. TypeScript makes it easier to write tests that ensure the correct types are used throughout your codebase.

interface Todo {
  title: string;
  description: string;
  completed: boolean;
}

type TodoPreview = Pick<Todo, 'title' | 'completed'>;

const todo: TodoPreview = {
  title: 'Buy groceries',
  completed: false
};

interface Todo {
  title: string;
  description: string;
  completed: boolean;
}

type TodoSummary = Omit<Todo, 'description'>;

const todo: TodoSummary = {
  title: 'Buy groceries',
  completed: false
};