Using async/await with for loop in nodejs

Asynchronous programming can be a bit tricky, especially when it comes to looping. In Node.js, the traditional for loop doesn’t play well with asynchronous functions, as the loop will continue to iterate before the asynchronous code inside of it has completed. This can lead to unexpected results and can be difficult to debug. One solution to this problem is to use the async and await keywords in conjunction with the for loop. In this article, we’ll take a look at how to use these keywords to create a more efficient and reliable asynchronous loop in Node.js.

Using async/await with for loop:

To use async/await with a for loop, you’ll need to create an async function that contains the loop. Within that function, you can use the await keyword to pause the execution of the loop until the asynchronous code inside of it has completed.

Here’s an example:

async function printFiles () {
  const files = await getFilePaths() 
  for (const file of files) {
    const contents = await fs.readFile(file, 'utf8')
    console.log(contents)
  }
}

Looping using map function to read in parallel in nodejs

async function printFiles () {
const files = await getFilePaths();
await Promise.all(files.map(async (file) => {
const contents = await fs.readFile(file, 'utf8')
console.log(contents)
}));
}

Using for-await-of loop:

Another way to handle this is by using the for-await-of loop. It’s a new addition of ECMAScript 2018 and it’s also very simple to use.

async function processData() {
  for await (const item of data) {
    let result = await asyncFunction(item);
    console.log(result);
  }
}

In this example, the asyncFunction is an asynchronous function that takes in an item and returns a result. The await keyword is used to pause the execution of the loop until the asyncFunction has completed. Once the function has completed, the result is logged to the console.

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