One way to combine two elements from an array in JavaScript is by comparing their dates (or any other similar element)

Question

One way to combine two elements from an array in JavaScript is by comparing their dates (or any other similar element)

Currently, the array is structured as follows:

array = [
 {
  date: '2020/06/12',
  hours: 8.4
 },
 {
  date: '2020/06/15',
  hours: 4.5
 },
 {
  date: '2020/06/12',
  hours: 3.8
 },
 {
  date: '2020/06/16',
  hours: 5.5
 },
]

The objective is to combine and filter out duplicated dates in order to sum their corresponding hours. For example, with the given array above where the day 12 occurs twice, the result should be as follows:

array = [
 {
  date: '2020/06/12',
  hours: 12.2
 },
 {
  date: '2020/06/15',
  hours: 4.5
 },
 {
  date: '2020/06/16',
  hours: 5.5
 },
]

javascript arrays lodash

Answer 1

Answer №1

To consolidate data, consider utilizing a reducer function:

const mergedData = dataArray.reduce((accumulator, current) => {
   const previous = accumulator.find(elem => elem.date === current.date);
    if(previous) {
        previous.hours += current.hours;
    } 
    else {
        accumulator.push(current);
    }
    return accumulator;
}
, []);

Answer 2

To consolidate data, consider utilizing a reducer function:

const mergedData = dataArray.reduce((accumulator, current) => {
   const previous = accumulator.find(elem => elem.date === current.date);
    if(previous) {
        previous.hours += current.hours;
    } 
    else {
        accumulator.push(current);
    }
    return accumulator;
}
, []);

Answer 3

Answer №2

function groupHoursByDate(arrayOfObjects, property) {
  let i = 0;
  let val;
  let index;
  const values = [];
  const result = [];
  for (; i < arrayOfObjects.length; i++) {
    val = arrayOfObjects[i][property];
    index = values.indexOf(val);
    if (index > -1) result[index].push(arrayOfObjects[i]);
    else {
      values.push(val);
      result.push([arrayOfObjects[i]]);
    }
  }

  const newArray = [];

  for (const x of result) {
    let totalHours = 0;
    let currentDate;
    for (const obj of x) {
      currentDate = obj.date;
      totalHours += obj.hours;
    }

    newArray.push({
      date: currentDate,
      hours: totalHours,
    });
  }

  return newArray;
};

// Call the groupHoursByDate function
const groupedHours = groupHoursByDate([{
    date: '2020/06/12',
    hours: 8.4
  },
  {
    date: '2020/06/15',
    hours: 4.5
  },
  {
    date: '2020/06/12',
    hours: 3.8
  },
  {
    date: '2020/06/16',
    hours: 5.5
  },
], "date");

console.log(groupedHours);

Answer 4

function groupHoursByDate(arrayOfObjects, property) {
  let i = 0;
  let val;
  let index;
  const values = [];
  const result = [];
  for (; i < arrayOfObjects.length; i++) {
    val = arrayOfObjects[i][property];
    index = values.indexOf(val);
    if (index > -1) result[index].push(arrayOfObjects[i]);
    else {
      values.push(val);
      result.push([arrayOfObjects[i]]);
    }
  }

  const newArray = [];

  for (const x of result) {
    let totalHours = 0;
    let currentDate;
    for (const obj of x) {
      currentDate = obj.date;
      totalHours += obj.hours;
    }

    newArray.push({
      date: currentDate,
      hours: totalHours,
    });
  }

  return newArray;
};

// Call the groupHoursByDate function
const groupedHours = groupHoursByDate([{
    date: '2020/06/12',
    hours: 8.4
  },
  {
    date: '2020/06/15',
    hours: 4.5
  },
  {
    date: '2020/06/12',
    hours: 3.8
  },
  {
    date: '2020/06/16',
    hours: 5.5
  },
], "date");

console.log(groupedHours);

One way to combine two elements from an array in JavaScript is by comparing their dates (or any other similar element)

Answer №1

Answer №2

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