Object Literals

In TypeScript (and JavaScript} and Object can be a value.

const person = {
    name: "Alice",
    age: 30,
    isEmployed: true
};

You can access the properties of an object using dot notation or bracket notation:

console.log(person.name); // "Alice"
console.log(person['age']); // 30

The type of the object is inferred here as { name: string; age: number; isEmployed: boolean; }. This means you cannot assign values of the wrong type to the properties:

person.name = 42; // Error: Type 'number' is not assignable to type 'string'
person.age = "thirty"; // Error: Type 'string' is not assignable to type 'number'
person.isEmployed = "yes"; // Error: Type 'string' is not assignable to type 'boolean'

You also cannot add new properties that are not defined in the object type:

person.address = "123 Main St"; // Error: Property 'address' does not exist on type '{ name: string; age: number; isEmployed: boolean; }'