Guided Notes
Object Types & Type Aliases
Describing object shapes inline, optional and readonly properties, index signatures, type aliases, and excess property checks.
Object types
Slide 1 / 4const patient: { name: string; age: number; ward?: string } = { name: "Neema", age: 34 };
• Each property has a type. • ? makes it optional — its type becomes string | undefined. • Missing required properties and misspelled properties are errors.
TypeScript also infers object types: const car = { make: "Toyota", year: 2019 } has type { make: string; year: number }.