async/await Examples in Node.js

Introduction

Asynchronous programming in Node.js can often lead to complex and hard-to-read code, especially when using traditional callback methods or Promises. The async/await syntax, introduced in ES2017, provides a more elegant way to work with asynchronous code, making it easier to read and maintain. In this article, we will explore three diverse examples of using async/await for cleaner asynchronous code in Node.js.

Example 1: Fetching Data from an API

Context

In this scenario, we will fetch data from a public API using the axios library. This example demonstrates a common use case for async/await—retrieving data asynchronously while keeping the code clean and understandable.

const axios = require('axios');

const fetchData = async (url) => {
  try {
    const response = await axios.get(url);
    console.log('Data:', response.data);
  } catch (error) {
    console.error('Error fetching data:', error);
  }
};

const apiUrl = 'https://jsonplaceholder.typicode.com/posts';
fetchData(apiUrl);

Notes

• Ensure you have the axios library installed in your project by running npm install axios.
• This code will log the fetched data to the console or output an error message if the request fails.

Example 2: Reading Files with Promises

Context

This example illustrates how to read files asynchronously using the fs module in Node.js. The async/await syntax can simplify error handling and improve readability when working with file operations.

const fs = require('fs').promises;

const readFileAsync = async (filePath) => {
  try {
    const data = await fs.readFile(filePath, 'utf8');
    console.log('File Content:', data);
  } catch (error) {
    console.error('Error reading file:', error);
  }
};

const filePath = './example.txt';
readFileAsync(filePath);

Notes

• Use fs.promises to get Promise-based functions for file operations.
• Make sure the file path is correct and that the file exists to avoid errors.

Example 3: Sequential API Calls

Context

In this example, we’ll demonstrate how to make multiple API calls sequentially using async/await. This is useful when the result of one API call is required for the next call.

const axios = require('axios');

const fetchPostAndComments = async (postId) => {
  try {
    const postResponse = await axios.get(`https://jsonplaceholder.typicode.com/posts/${postId}`);
    console.log('Post:', postResponse.data);

    const commentsResponse = await axios.get(`https://jsonplaceholder.typicode.com/posts/${postId}/comments`);
    console.log('Comments:', commentsResponse.data);
  } catch (error) {
    console.error('Error fetching data:', error);
  }
};

const postId = 1;
fetchPostAndComments(postId);

Notes

• This example fetches a post and its comments sequentially, meaning the comments are only fetched after the post has been retrieved.
• The use of async/await here simplifies the flow of asynchronous logic, making it easier to follow.

By utilizing async/await in these examples, we can see how it enhances code readability and simplifies error handling in Node.js. Whether fetching data from APIs, reading files, or making sequential API calls, async/await offers a cleaner approach to managing asynchronous operations.