What can I do to reduce this code's complexity

Question

I need to get the data using locationid or default in the below nodejs code, the code works, but how can I reduce the complexity? If day is selected, retrieve the data of the day loop by using the values given if locationid is null or not.

  if (filter_by === 'Day') {
    //12 hrs in a day
    graph_data = graph_data_of_day;
    query = {
      created_at: {
        gt: current_date,
      },
      ref: headerData ?.ref,
    };
  } else if (filter_by === 'Week') {
    // 7 days a week
    graph_data = graph_data_of_weeks;
    query = {
      created_at: {
        gte: startofweek_date,
        lte: endofweek_date,
      },
      ref: headerData ?.ref,
    };
  } else if (filter_by === 'Month') {
    // 4 weeks in a month
    graph_data = graph_data_of_months;
    query = {
      created_at: {
        gte: startOfMonth_date,
        lte: endOfMonth_date,
      },
      ref: headerData ?.ref,
    };
  } else if (filter_by === 'Year') {
    // 12 months_for_year in a year
    graph_data = graph_data_of_year;
    query = {
      created_at: {
        gte: startOfYear_date,
        lte: endOftheYear_date,
      },
      ref: headerData ?.ref,
    };
  } else if (filter_by === 'custom') {
    graph_data = [1, 2, 3, 4, 5, 7, 3, 12, 4, 2, 5, 6];
    query = {
      created_at: {
        gte: custom_start_date,
        lt: custom_end_date,
      },
    };
  }

Answer 1

 graph_store = {
        'Day': graph_data_of_day,
        'Week': graph_data_of_weeks,
        'Month': graph_data_of_months,
        'Year': graph_data_of_year,
        'custom': [1, 2, 3, 4, 5, 7, 3, 12, 4, 2, 5, 6]
    };


buildQuery(location_id, graph_store, graphType, start, end){
   
    graph_data = graph_store[graphType];

    query = {
        created_at: {
            gt: start
        }
    };

if (graphType !== 'custom' && location_id !== '')Object.assign(query, {ref: headerData ? .ref})
if (graphType !== 'Day') Object.assign(query.created_at, {lte: end});
if (location_id !== '') Object.assign(query, {location_id: location_id});

return [graph_data,query];

}

When you break the filters down, there are only 3 actual difference's in your query object.

1. Is it not a "Day", then add the "lte" property to "query.created_at".

2. Does it have location, then add "location_id" property to "query".

3. The "ref: headerData ? .ref" is a special case. Every query object has this property except "no location" and "custom".

Build the graph_store outside of the Querybuilder. There are too many operations within your block of code.

Return the query and data as an array of Objects.

Answer 2

We can immediately halve it using these two lines

let query = {};
if (location_id) query.location_id = location_id;

then we can have an object keyed by filter_by to make the complete code like this:

const filterData = { 
  "Day":    { graph_data: graph_data_of_day,    created_at: { gt: current_date }},
  "Week":   { graph_data: graph_data_of_weeks,  created_at: { gte: startOfWeek_date,  lte: endOfWeek_date    }},
  "Month":  { graph_data: graph_data_of_months, created_at: { gte: startOfMonth_date, lte: endOfMonth_date   }},
  "Year":   { graph_data: graph_data_of_year,   created_at: { gte: startOfYear_date,  lte: endOfYear_date }},
  "custom": { graph_data: graph_data_custom,    created_at: { gte: custom_start_date, lt: custom_end_date }}
};

let query = {};
if (location_id) query.location_id = location_id;
let { graph_data, created_at } = filterData[filter_by]; // spread is setting graph_data here.
query.created_at = created_at; // from the spread above
//    query.ref = headerData ? headerData : .ref; // not sure what .ref is.

console.log(graph_data,query)

<script>
const getDateString = date => date.toISOString().split("T")[0];
// testing: 
let filter_by="Month",                      // your data here  
location_id = "loc 1",                      // your data here 
graph_data_of_day    = ["day1","day2"],     // your data here 
graph_data_of_weeks  = ["week1","week2"],   // your data here 
graph_data_of_months = ["month1","month2"], // your data here 
graph_data_of_year   = ["year1","year2"],   // your data here 
graph_data_custom    = [1, 2, 3, 4, 5, 7, 3, 12, 4, 2, 5, 6], // your data here 
today = new Date(),
current_date = getDateString(today),
startOfWeek_date  = getDateString(new Date()), // I assume you have this code
endOfWeek_date    = getDateString(new Date()), // I assume you have this code
startOfMonth_date = getDateString(new Date(today.getFullYear(),today.getMonth(),1,15,0,0,0)),
endOfMonth_date   = getDateString(new Date(today.getFullYear(),today.getMonth()+1,0,15,0,0,0)),
startOfYear_date  = getDateString(new Date(today.getFullYear(),0,1,15,0,0,0)),
endOfYear_date    = getDateString(new Date(today.getFullYear()+1,0,0,15,0,0,0)),
custom_start_date = getDateString(new Date()), // your code here
custom_end_date   = getDateString(new Date()); // your code here

</script>