How can i return two objects in javascript

user_14281274 0
Viewed 659

As an example

I have two arrays

const tempData = [
          { day: "Mon", temp: 33.6 },
          { day: "Tue", temp: 34.6 },
          { day: "Wed", temp: 33.1 },
          { day: "Fri", temp: 35.6 }
        ];
const coughData = [
          { day: "Mon", count: 2 },
          { day: "Wed", count: 1 },
          { day: "Thur", count: 1 },
          { day: "Fri", count: 3 },
          { day: "Sat", count: 1 }
        ];

I need to merge these arrays into one so that if the day matches the count value adds to that object if it doesn't match it adds both objects to the array.

Don't know if the explanation isn't so clear but

The expected result should be like this:

const data = [
          { day: "Mon", temp: 33.6, count: 2 },
          { day: "Tue", temp: 34.6 },
          { day: "Wed", temp: 33.1, count: 1 },
          { day: "Thur", count: 1 },
          { day: "Fri", temp: 35.6, count: 3 },
          { day: "Sat", count: 1 }
        ];

I am trying to use map function like so but can't understand how do I return both the objects if they don't match:

const data = tempData.map(temp => {
          coughData.map(cough => {
            if (temp.day === cough.day) {
              return (temp.count = cough.count);
            } else {
              return cough;
            }
          });
          return temp;
        });
arrays javascript
5 Answers

You could collect all data grouped by day in an object and get the values as result set.

const
    addToCollection = (collection, key) => o => Object.assign(collection[o[key]] ??= {}, o),
    tempData = [{ day: "Mon", temp: 33.6 }, { day: "Tue", temp: 34.6 }, { day: "Wed", temp: 33.1 }, { day: "Fri", temp: 35.6 }],
    coughData = [{ day: "Mon", count: 2 }, { day: "Wed", count: 1 }, { day: "Thur", count: 1 }, { day: "Fri", count: 3 }, { day: "Sat", count: 1 }],
    collection = {};
    
tempData.forEach(addToCollection(collection, 'day'));
coughData.forEach(addToCollection(collection, 'day'));

console.log(Object.values(collection));
.as-console-wrapper { max-height: 100% !important; top: 0; }

user_14476750

You can first merge the objects of the arrays, and then use .reduce() along with a Map to accumulate the values. The Map can be keyed by the day property, which will allow you to group related object properties together. You can then use Array.from() to transform your Map back into an array of objects like so:

const tempData = [{ day: "Mon", temp: 33.6 }, { day: "Tue", temp: 34.6 }, { day: "Wed", temp: 33.1 }, { day: "Fri", temp: 35.6 }];
const coughData = [{ day: "Mon", count: 2 }, { day: "Wed", count: 1 }, { day: "Thur", count: 1 }, { day: "Fri", count: 3 }, { day: "Sat", count: 1 }];

const arr = [...tempData, ...coughData];

const result = Array.from(arr.reduce((map, {day, ...rest}) => {
  const seen = map.get(day) || {day};
  return map.set(day, {...seen, ...rest});
}, new Map).values());

console.log(result);

user_56489540 
let newArray = Array();
let longer = (tempData.length <= coughData.length) ? coughData.length : 
tempData.length;
for(let i = 0, j = 0; i < longer; ++i, ++j) {
    newArray.push(Object.assign(coughData[i], tempData[j]));
}

Print to console:

[ { day: 'Mon', count: 2, temp: 33.6 },
{ day: 'Tue', count: 1, temp: 34.6 },
{ day: 'Wed', count: 1, temp: 33.1 },
{ day: 'Fri', count: 3, temp: 35.6 },
{ day: 'Sat', count: 1 } ]
user_121071820 

const tempData = [
    { day: "Mon", temp: 33.6 },
    { day: "Tue", temp: 34.6 },
    { day: "Wed", temp: 33.1 },
    { day: "Fri", temp: 35.6 }
];
const coughData = [
    { day: "Mon", count: 2 },
    { day: "Wed", count: 1 },
    { day: "Thur", count: 1 },
    { day: "Fri", count: 3 },
    { day: "Sat", count: 1 }
];

const tempRes = [...tempData, ...coughData];
const result = tempRes.reduce((acc, curr) => {
    const { day, ...rest } = curr;
    acc[day] = acc[day] ? Object.assign({}, acc[day], rest) : curr
    return acc;
}, {})
console.log(Object.values(result))
.as-console-wrapper { max-height: 100% !important; top: 0; }

user_123788990

You can use Object.assign() javascript function. The Object.assign () method is used to copy the values ​​of all the enumerable properties of one or more source objects to a target object. This method will return the target object

Like so:

const target = { a: 1, b: 2 };
const source = { b: 4, c: 5 };

const returnedTarget = Object.assign(target, source);

console.log(target);
// expected output: Object { a: 1, b: 4, c: 5 }

console.log(returnedTarget);
// expected output: Object { a: 1, b: 4, c: 5 }

https://developer.mozilla.org/pt-BR/docs/Web/JavaScript/Reference/Global_Objects/Object/assign

user_141387150
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