Readonly

Readonly constructs a type with all properties of Type set to readonly, meaning the properties of the constructed type cannot be reassigned.

interface Todo {
  title: string;
}

const todo: Readonly<Todo> = {
  title: 'Delete inactive users',
};

// Cannot assign to 'title' because it is a read-only property.
todo.title = 'Hello';

Learn more from the following links:

• Readonly