In TypeScript, a class is defined using the class keyword. Here's an example of how to declare a class in TypeScript:
class Person {
name: string;
age: number;
constructor(name: string, age: number) {
this.name = name;
this.age = age;
}
sayHello(): void {
console.log(Hello, my name is ${this.name} and I'm ${this.age} years old);
}
}
let person = new Person("John", 30);
person.sayHello();
In this example, we have defined a Person class with two properties: name of type string and age of type number. We have also defined a constructor that takes in two parameters, name and age, and assigns them to the class properties.
Additionally, we have defined a method called sayHello which logs out a message to the console using the class properties.
To create a new instance of the Person class, we use the new keyword followed by the class name and passing in the required parameters to the constructor. Finally, we call the sayHello method on the person instance to log out the message.