How to use the parallelLimit function from async

async.parallelLimit is a function in the Async.js library for Node.js that runs multiple asynchronous functions in parallel with a maximum limit on the number of simultaneous executions.

How does async.parallelLimit work?

When you use async.parallelLimit in your Node.js code, you are using a function that runs multiple asynchronous functions in parallel with a maximum limit on the number of simultaneous executions. To use async.parallelLimit, you pass an array of asynchronous functions as the first argument, and a limit on the maximum number of simultaneous executions as the second argument. The functions are executed in parallel, up to the specified limit. Here is an example of using async.parallelLimit to run multiple asynchronous functions in parallel with a limit of 3 simultaneous executions: javascript Copy code {{{{{{{ const async = require('async'); const tasks = [ (callback) => { setTimeout(() => { console.log('Task 1 complete'); callback(null, 1); }, 1000); }, (callback) => { setTimeout(() => { console.log('Task 2 complete'); callback(null, 2); }, 2000); }, (callback) => { setTimeout(() => { console.log('Task 3 complete'); callback(null, 3); }, 1500); }, (callback) => { setTimeout(() => { console.log('Task 4 complete'); callback(null, 4); }, 500); }, ]; async.parallelLimit(tasks, 3, (err, results) => { if (err) { console.error(err); } else { console.log(results); } }); In this example, we are using async.parallelLimit to run an array of four asynchronous functions in parallel, with a limit of 3 simultaneous executions. Each asynchronous function simulates a task that takes a different amount of time to complete using setTimeout. The callback function is called when each task is complete, passing the results of the task as an argument. After all tasks have completed, the final callback function is called with an error or the results of the tasks as arguments. We log the results of the tasks to the console. Overall, async.parallelLimit provides a simple and powerful way to run multiple asynchronous functions in parallel with a maximum limit on the number of simultaneous executions, allowing you to optimize performance and improve efficiency in your Node.js applications.

Ai Example

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const async = require("async");

const tasks = [
  (callback) => {
    setTimeout(() => {
      console.log("Task 1 complete");
      callback(null, 1);
    }, 1000);
  },
  (callback) => {
    setTimeout(() => {
      console.log("Task 2 complete");
      callback(null, 2);
    }, 2000);
  },
  (callback) => {
    setTimeout(() => {
      console.log("Task 3 complete");
      callback(null, 3);
    }, 1500);
  },
  (callback) => {
    setTimeout(() => {
      console.log("Task 4 complete");
      callback(null, 4);
    }, 500);
  },
];

async.parallelLimit(tasks, 2, (err, results) => {
  if (err) {
    console.error(err);
  } else {
    console.log(results);
  }
});

In this example, we are using async.parallelLimit to run an array of four asynchronous functions in parallel, with a limit of 2 simultaneous executions. Each asynchronous function simulates a task that takes a different amount of time to complete using setTimeout. The callback function is called when each task is complete, passing the results of the task as an argument. After all tasks have completed, the final callback function is called with an error or the results of the tasks as arguments. We log the results of the tasks to the console. Note that in this example, only two tasks are running at any given time due to the limit of 2 simultaneous executions specified in the async.parallelLimit call.