How do union and intersection types work in TypeScript?

Union and intersection types provide powerful ways to combine types in TypeScript. Union Types (|): Allow a value to be one of several types: type StringOrNumber = string | number; type Status = 'loading' | 'success' | 'error'; function printId(id: string | number) { if (typeof id === 'string') { console.log(id.toUpperCase()); } else { console.log(id.toFixed(2)); } } Intersection Types (&): Combine multiple types into one, requiring all properties: interface Person { name: string; age: number; } interface Employee { employeeId: number; department: string; } type PersonEmployee = Person & Employee; const worker: PersonEmployee = { name: 'John', age: 30, employeeId: 123, department: 'IT' }; Key Differences: • Union: Value can be ANY of the types • Intersection: Value must have ALL properties from combined types • Union narrows with type guards • Intersection creates new composite type.