Typescript Function

Typescript function

Created By: chatGPT

TypeScript is a superset of JavaScript that adds static typing to the language. In this tutorial, we will create a simple TypeScript function. We'll learn how to define a function, specify the types of parameters, and define the return type.

function greet(name: string): string {
    return `Hello, ${name}!`;
}

const userName: string = 'Alice';
console.log(greet(userName));

In the example above, we defined a function called greet. It takes a single parameter, name, which is of type string. The function also has a return type of string. In the last part, we declare a variable userName and pass it to the greet function, logging the result to the console.

function add(a: number, b: number): number {
    return a + b;
}

const sum: number = add(5, 10);
console.log(`The sum is: ${sum}`);

Here, we created another function called add that takes two parameters, a and b, both of type number. The function returns their sum also as a number. We then invoke it with two numbers and log the output to the console.

function multiply(a: number, b: number): number {
    return a * b;
}

console.log(`5 multiplied by 10 is: ${multiply(5, 10)}`);

This is another example of a function named multiply that performs multiplication. It takes two numbers and returns their product. The result is immediately logged to the console.

function isEven(num: number): boolean {
    return num % 2 === 0;
}

console.log(`Is 4 even? ${isEven(4)}`);

The isEven function checks if a number is even. It takes a number as a parameter and returns a boolean indicating whether the number is even. We call this function and log the result.

function calculateCircleArea(radius: number): number {
    return Math.PI * radius * radius;
}

console.log(`Area of circle with radius 5: ${calculateCircleArea(5)}`);

Finally, we created a function called calculateCircleArea that calculates the area of a circle given its radius. The area is calculated using the formula πr². The output is displayed in the console, showcasing how we can work with mathematical functions in TypeScript.

interface Person {
    name: string;
    age: number;
}

function greetPerson(person: Person): string {
    return `Hello, my name is ${person.name} and I am ${person.age} years old.`;
}

const individual: Person = { name: 'John', age: 30 };
console.log(greetPerson(individual));

Using interfaces in TypeScript allows us to define the structure of an object. In the greetPerson function, we use an interface named Person that has properties name and age. The function uses this interface to ensure that the passed argument satisfies the expected structure.

function fetchData(url: string): Promise<any> {
    return fetch(url)
        .then(response => response.json())
        .catch(error => console.error('Error fetching data:', error));
}

fetchData('https://api.example.com/data')
    .then(data => console.log(data));