Asynchronous JavaScript: A Deep Dive into Callbacks, Promises, and Async/Await

Callbacks, Promises, and Async/Await 

Callbacks:

A callback is a function that is passed as an argument to another function and is executed inside that function. Callbacks are often used to handle asynchronous code in JavaScript. Here's an example:

function getData(callback) {

 setTimeout(() => {

 const data={ name: "John", age: 30 };

    callback(data);

  }, 2000);

}

getData((data) => {

  console.log(data);

});

In this example, getData is a function that takes a callback function as an argument. Inside the getData function, we use setTimeout to simulate a delay and then call the callback function with some data. We then call getData and pass in a callback function that logs the data to the console.

Promises:

A promise is an object that represents a value that may not be available yet. Promises are often used to handle asynchronous code in a more organized and efficient way than callbacks. Here's an example:

function getData() {

 return new Promise((resolve, reject) => {

 setTimeout(() => {

 const data = { name: "John", age: 30 };

 resolve(data);

    }, 2000);

  });

}

getData().then((data) => {

  console.log(data);

});

In this example, getData returns a new Promise that resolves with some data after a delay. We then call getData and use the .then() method to handle the resolved value.

Async/Await:

Async/await is a syntax for handling asynchronous code that was introduced in ES2017. It allows you to write asynchronous code that looks and behaves like synchronous code, making it easier to read and understand. Here's an example:

function getData() {

return new Promise((resolve, reject) => {

 setTimeout(() => {

const data = { name: "John", age: 30 };

resolve(data);

}, 2000);

  });

}

async function fetchData() {

  const data = await getData();

  console.log(data);

}

fetchData();

In this example, fetchData is an async function that uses the await keyword to wait for the getData Promise to resolve before logging the data to the console. We then call fetchData to initiate the asynchronous code.

I hope these examples help you understand callbacks, promises, and async/await in JavaScript better!

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