How to fill in missing months of last year in an array using javascript-CodePudding

I have an array of months and its count as follows:

[
            {
                "registered_to_month": "04-2022",
                "count": "3"
            },
            {
                "registered_to_month": "03-2022",
                "count": "4"
            },
            {
                "registered_to_month": "02-2022",
                "count": "6"
            },
            {
                "registered_to_month": "01-2022",
                "count": "6"
            },
            {
                "registered_to_month": "11-2021",
                "count": "11"
            }
        ]

This result I am getting last 12 months The months which is not available I want to replace with 0 so that I can plot in the graph. I am not able to figure out how can I solve this.

CodePudding user response：

You can have an array of 12 elements with all values initially 0 and loop on all values you have. Add count to array as

var counts = new Array(12).fill(0);
var values = JSON.parse(your_string_with_json);
for (var i= 0; i<values.length; i  )
{
  var month = values[i].registered_to_month.split('-')[0];
  counts[parseInt(month)] = values[i].counts;
}
var allvalues;
for(var j= 0; j<counts.length; j  )
{
  var val = {
    registered_to_month: j<10 ? '0'   j : j,
    count: counts[j]
  };
  allvalues.push(val);
}

CodePudding user response：

We'll first generate an array of dates from the start date to the end date in the given data. Then compare which date exists in the given data. If a date exists in the given data, it is pushed to the result array else a new item is added to the result array with count as 0.

data = [
    {
        "registered_to_month": "04-2022",
        "count": "3"
    },
    {
        "registered_to_month": "03-2022",
        "count": "4"
    },
    {
        "registered_to_month": "02-2022",
        "count": "6"
    },
    {
        "registered_to_month": "01-2022",
        "count": "6"
    },
    {
        "registered_to_month": "11-2021",
        "count": "11"
    }
]

const generateAllDates = (startDate, endDate) =>{
  var dates = [];
  var startDateYr = startDate.split('-')[1];
  var startDateMon = startDate.split('-')[0];
  var endDateYr = endDate.split('-')[1];
  var endDateMon = endDate.split('-')[0];
  
  for(var year = startDateYr; year <= endDateYr; year  ) {
      for(var month = startDateMon; month <= 12; month  ) {
          dates.push(month.toString().padStart(2, "0") "-" year);
          if (year >= endDateYr && month >= endDateMon) break;
      };
      startDateMon = 1;
  };
  return dates.reverse();
}

const fillMissingData = (data) =>{
  // assuming the dates in data are arranged
  // in descending order, sort first if otherwise
  const startDate = data[data.length-1]["registered_to_month"]
  const endDate = data[0]["registered_to_month"]
  const allDates = generateAllDates(startDate, endDate)
  var resultData = []
  
  for (const genDate of allDates){
    let exists = true
    for(const item of data){
      date = item["registered_to_month"]
      if (genDate == date){
        exists = true
        resultData.push(item);
        break
      }else{
        exists = false
      }
    }
    if (!exists){
      resultData.push({"registered_to_month": genDate, "count": '0'})
    } 
  } 
  return resultData;
  return resultData;
}

fillMissingData(data)