iterate over collection async in javascript

To iterate over a collection asynchronously in JavaScript, you can use the for...of loop in combination with async and await.

Assuming that you have an array of items, the following code demonstrates how to iterate over each of the items in the array asynchronously:

index.tsx
const items = [1, 2, 3, 4, 5];

async function processItems() {
  for (const item of items) {
    await doSomethingAsync(item);
  }
}

function doSomethingAsync(item) {
  return new Promise(resolve => {
    setTimeout(() => {
      console.log(`processing item ${item}`);
      resolve();
    }, 1000);
  });
}

processItems();
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In this example, we have an array of items, and we define an async function called processItems to iterate over each item in the array using a for...of loop. We then await the execution of an asynchronous function called doSomethingAsync on each item.

The doSomethingAsync function returns a Promise that resolves after a 1-second delay, simulating some asynchronous operation. In this example, we're simply logging a message to the console.

By using await to yield control flow to the event loop on each iteration, we ensure that the asynchronous operation is completed before moving on to the next item in the array.

You can modify the doSomethingAsync function to perform any asynchronous operation you need, such as making an API request, reading from a file, or interacting with a database.