How To Set Reminder Using Jquery?

In the database, project_details table is there. I am fetching the data from database and result like json given below; Recurrence start date is there in the database table but I a

Solution 1:

Although you hadn't got past the point of assigning the results from the AJAX into an array (because you had inputList outside the for loop, where the values were not defined or looped over), in the end there were so many other small things wrong with the code, especially inside the getPaymentPlan function that it's impossible to list them all here. Instead I simply provide a working version for you to study and learn from.

Also your expected results as stated in the question are incorrect - you've asked for it to show the reminder date, but then what you've listed are the recurrence dates. All the reminder dates are several days earlier (as controlled by the reminder_set_days property).

The results my demo produces show the actual reminder date instead:

$('#find_recurrence').click(function(event) {
  var fromdate_recu_view = $('#fromdate_recu_view').val(); //2025-01-01
  var todate_recu_view = $('#todate_recu_view').val(); //2026-01-30

  //hard-code data instead of AJAX, for this demo:
  let new_data = {
    "projectremindshow": [{
        "project_ID": "8",
        "project_title": "abc",
        "period_type": "Yearly",
        "recurrence_date": "2021-10-28",
        "reminder_set_days": "12",
        "recur_every": "2",
        "start_date": "2021-09-28"
      },
      {
        "project_ID": "10",
        "project_title": "xyz",
        "period_type": "Yearly",
        "recurrence_date": "2021-10-05",
        "reminder_set_days": "13",
        "recur_every": "4",
        "start_date": "2021-09-05"
      },
      {
        "project_ID": "11",
        "project_title": "mno",
        "period_type": "Monthly",
        "recurrence_date": "2021-10-01",
        "reminder_set_days": "10",
        "recur_every": "8",
        "start_date": "2021-09-21"
      }
    ]
  };

  let inputList = [];

  for (var i = 0; i < new_data.projectremindshow.length; i++) {
    var proj = new_data.projectremindshow[i];

    //add a new entry to inputList for each entry returned from the AJAX call
    inputList.push({
      dateFrom: new Date(fromdate_recu_view),
      dateTo: new Date(todate_recu_view),
      daysBefore: proj.reminder_set_days,
      recurrenceDate: new Date(proj.start_date),
      period: proj.period_type,
      skip: proj.recur_every,
      title: proj.project_title
    });
  }

  const frequencyList = inputList.map((el, index) => {
    return getPaymentPlan(el)
  });
  console.log(frequencyList);
});

/* the getPaymentPlan function is standalone, it should not be within a loop or within any other callback functions! */
const getPaymentPlan = ({
  dateFrom,
  dateTo,
  recurrenceDate,
  daysBefore,
  period,
  skip,
  title
}) => {
  //start from either the recurrence start date, or the start date in the form - whichever is later
  let startDate = (recurrenceDate.getTime() > dateFrom.getTime() ? recurrenceDate : dateFrom);
  //reminders go out several days before the actual recurrence start date
  startDate = startDate.subtractDays(daysBefore);

  let recurObj = {
    "project": title,
    "recurrenceList": []
  }

  while (startDate.getTime() <= dateTo.getTime()) {
    recurObj.recurrenceList.push(startDate.toISOString().split('T')[0]);

    switch (period) {
      case 'Monthly':
        startDate = startDate.addMonths(parseInt(skip));
        break;
      case 'Yearly':
        startDate.setFullYear(startDate.getFullYear() + parseInt(skip));
        break;
      default:
        recurObj.recurrenceList.push("wrong period type is given")
        break;
    }
  }

  return recurObj;
}

/* below are some functions to correctly add / subtract days and months from a Date, accounting for leap years, differing month lengths, etc */
Date.prototype.addDays = function(days) {
  var date = new Date(this.valueOf());
  date.setDate(date.getDate() + days);
  return date;
}

Date.prototype.subtractDays = function(days) {
  var date = new Date(this.valueOf());
  date.setDate(date.getDate() - days);
  return date;
}

Date.prototype.addMonths = function(months) {
  var date = new Date(this.valueOf());
  var d = date.getDate();
  date.setMonth(date.getMonth() + months);
  if (date.getDate() != d) {
    date.setDate(0);
  }
  return date;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
From date: <input type="date" id="fromdate_recu_view" /><br/> To date: <input type="date" id="todate_recu_view"><br/>
<button id="find_recurrence">Find Recurrence</button>

Here is an alternative version of the getPaymentPlan function which will output the data in a format which may be easier to sort, and also to output later according to your desired HTML format:

const getPaymentPlan = ({
  dateFrom,
  dateTo,
  recurrenceDate,
  daysBefore,
  period,
  skip,
  title
}) => {
  //start from either the recurrence start date, or the start date in the form - whichever is later
  let startDate = (recurrenceDate.getTime() > dateFrom.getTime() ? recurrenceDate : dateFrom);
  //reminders go out several days before the actual recurrence start date
  startDate = startDate.subtractDays(daysBefore);

  let recurrenceList = [];

  while (startDate.getTime() <= dateTo.getTime()) {
    recurrenceList.push({ "project": title, "reminderDate": startDate.toISOString().split('T')[0] });

    switch (period) {
      case 'Monthly':
        startDate = startDate.addMonths(parseInt(skip));
        break;
      case 'Yearly':
        startDate.setFullYear(startDate.getFullYear() + parseInt(skip));
        break;
      default:
        recurrenceList.push({ "project": "wrong period type is given", "reminderDate": null })
        break;
    }
  }

  return recurrenceList;
}