Snippet for Running async tasks in parallel

AsyncTasksParallelExecution.js

/**generates async tasks */
function asyncTask() {
  return new Promise((resolve, reject) => {
    let val = Math.floor(Math.random() * 10);
    if (val > 5) {
      resolve(val);
    } else {
      reject(val);
    }
  });
}

let taskList = [
  asyncTask(),
  asyncTask(),
  asyncTask(),
  asyncTask(),
  asyncTask(),
  asyncTask(),
  asyncTask(),
  asyncTask(),
  asyncTask(),
];

/**function for running all async tasks parallely and appending their result/error in array */
function executeParallelTasks(taskList, callback) {
  let results = [];
  let errors = [];
  let completed = 0;

  taskList.forEach((task) => {
    task
      .then((res) => {
        results.push(res);
      })
      .catch((err) => {
        errors.push(err);
      })
      .finally(() => {
        completed = completed + 1;
        if (completed >= taskList.length) {
          callback(results, errors);
        }
      });
  });
}

/**call the parallel execution tasks function with callback */
executeParallelTasks(taskList, (results, errors) => {
  console.log("results:: ", results);
  console.log("errors:: ", errors);
});