Wsrtjtyk

console.clear();

/**

 *  Promises will wait for each other and will return any.

 *  If a promise is rejected it will stop.

 *  @param arr - (Promise<any> | ()=>Promise<any>) - Accepts promise or a function that returns a promise

 *  @param callback(response, index) - If callback 'returns' it will overwrite the current response. Useful for changing the response.

 *  @returns any

 */

const PromiseAllSeq = (arr, callback) => {



  let result = ;



  if (typeof callback !== 'function') {

    callback = () => {};

  }



  const rec = (arr) => {



    return new Promise((resolve, reject) => {



      if (arr.length) {



        (typeof arr[0] === 'function' ? arr[0]() : arr[0]).then(res => {



          let cb = callback(res, result.length);



          result = result.concat(typeof cb !== 'undefined' ? cb : res);



          arr.splice(0, 1);



          resolve(arr.length ? rec(arr) : result);



        }).catch(err => {



          reject(err);



        })



      } else {



        resolve(result);



      }



    })



  }



  return rec(arr);



}



function succesHandler(data, index) {



  // Here i can alter 'data'

  data['finishedPromiseNr'] = index;



  console.log("promise test ", data, index);



  console.log("Go for next ");



  return data;



}



function errorHandler(err) {

  console.log("Error occurred ", err);

}



function submitAjaxData(form, datafield) {

  console.log("called submitAjaxData  ", datafield);

  //var loadurl = domainName + "/ajax-call-handler";



  // Mock some requests with delayed responses

  // https://reqres.in/#console

  var loadurl = "https://reqres.in/api/users?delay=" + datafield.fakeDelay;

  return $.ajax({

    url: loadurl,

    method: "GET",

    data: datafield

  });

}



function formPostSubmission(form) {

  var parts = ['a', 'b', 'c'];

  var i = 0;

  let poll = ;

  parts.forEach(function(entry) {

    i++;



    // 'datafield' was not assigned with var or let

    // Reassigning it on each loop will allow 'datafield' to pass in the anonymous function below

    let datafield = {

      answer: entry,

      displayOrder: i,

      ajaxName: 'statementPartialSubmit',

      fakeDelay: parts.length - i

    };



    // Wrong: submitAjaxData is called, that means, the requests are sent immediately.

    // poll.push( $.when(submitAjaxData(form, datafield) );



    // Correct: Wrap and return $.when into a function otherwise 'submitAjaxData' will trigger the requests

    poll.push(() => $.when(submitAjaxData(form, datafield)));



  });



  PromiseAllSeq(poll, succesHandler).then(responseList => {



    console.log('final response');

    console.log(responseList);



  }).catch(errorHandler)





}



formPostSubmission(null);

<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>