Sum the properties of array of object types and join them as single object

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Need to sum the score and total_score of distinct objects based on subject names property.

Input data :

var data = [{
  name: "One",
  maths: {
    score: 2,
    total_score: 4
  },
  science: {
    score: 2,
    total_score: 4
  },
  social: {
    score: 2,
    total_score: 4
  }
}, {
  name: "One",
  maths: {
    score: 3,
    total_score: 4
  },
  science: {
    score: 1,
    total_score: 4
  },
  english: {
    score: 4,
    total_score: 4
  }
}]

Expected Output :

{
  name: "One",
  maths: {
    score: 5,
    total_score: 8
  },
  science: {
    score: 3,
    total_score: 8
  },
  social: {
    score: 2,
    total_score: 4
  },
  english: {
    score: 4,
    total_score: 4
  }
}

I have tried this :

data.forEach(function (a) {
    if (!this[a.name]) {
        this[a.name] = { name: a.name, contributions: 0 };
        result.push(this[a.name]);
    }
    this[a.name].contributions += a.contributions;
}, Object.create(null));

But it does not work for my case. Where the contributions object is different i.e Subject names are different each time.

Thanks in advance folks!

Javascript: how to merge multiple objects with sum of values, Need to sum the score and total_score of distinct objects based on subject names property. Input data : var data = [{ name: "One  I understand that in order to sum array elements in Ruby one can use the inject method, i.e. array = [1,2,3,4,5]; puts array.inject(0, &:+) But how do I sum the properties of objects within an object array e.g.? There's an array of objects and each object has a property "cash" for example. So I want to sum their cash balances into one total.

You can use Array.reduce():

var data = [{
    name: "One",
    maths: {
      score: 2,
      total_score: 4
    },
    science: {
      score: 2,
      total_score: 4
    },
    social: {
      score: 2,
      total_score: 4
    }
  },
  {
    name: "One",
    maths: {
      score: 3,
      total_score: 4
    },
    science: {
      score: 1,
      total_score: 4
    },
    english: {
      score: 4,
      total_score: 4
    }
  },
  {
    name: "Two",
    maths: {
      score: 3,
      total_score: 4
    },
    science: {
      score: 1,
      total_score: 4
    },
    english: {
      score: 4,
      total_score: 4
    }
  },
  {
    name: "Two",
    maths: {
      score: 3,
      total_score: 5
    },
    science: {
      score: 1,
      total_score: 5
    },
    english: {
      score: 4,
      total_score: 6
    }
  }
];
var res = data.reduce((acc, item)=>{
  var exist = acc.find(({name}) => name === item.name);
  if(exist){
    Object.keys(item).forEach((key) =>{
      if(key !== 'name'){
        if(exist[key]){
          exist[key].total_score += item[key].total_score;
          exist[key].score += item[key].score
        } else {
           exist[key] = item[key]
        }
      }
    });
  } else {
    acc.push(item);
  }
  return acc;
}, []);
console.log(res);

Data Structures: Objects and Arrays :: Eloquent JavaScript, Assume we have an array of objects - baskets with fruits. const fruits There are different types of fruits with different quantities in each All objects (baskets) in the array merged into one with the sum of each property's (fruit)  Sum javascript object propertyA values with same object propertyB in array of objects (9 answers) Closed 4 years ago . I would like to Group Object of Array by Id and sum by quantity in Jquery?

You could take an array as temporary result for reducing and look for the object with the same name and update all futher properties.

var data = [{ name: "One", maths: { score: 2, total_score: 4 }, science: { score: 2, total_score: 4 }, social: { score: 2, total_score: 4 } }, { name: "One", maths: { score: 3, total_score: 4 }, science: { score: 1, total_score: 4 }, english: { score: 4, total_score: 4 } }],
    result = data.reduce((r, o) => {
        var temp = r.find(({ name }) => name === o.name);
        if (!temp) {
            r.push(temp = { name: o.name });
        }
        Object.entries(o).forEach(([k, p]) => {
            if (k === 'name') return;
            temp[k] = temp[k] || {};
            ['score', 'total_score'].forEach(l => temp[k][l] = (temp[k][l] || 0) + o[k][l]);
        });
        return r;
    }, []);

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

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Arrays, The arrays are objects, so we can try to use delete : isConcatSpreadable property, then it's treated as an array by concat : its elements are  Objects and arrays (which are a specific kind of object) provide ways to group several values into a single value. Conceptually, this allows us to put a bunch of related things in a bag and run around with the bag, instead of wrapping our arms around all of the individual things and trying to hold on to them separately.

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Useful Javascript Array and Object Methods, The single value that results from the reduction. can be up to four possible output types without initialValue , as shown in the following example: To sum up, the values contained in an array of objects, you must supply an property) { return objectArray.reduce(function (acc, obj) { let key = obj[property] if  Adds a point or array object to the end of the array. append (value) Appends an object to the array in the last position. clone (point_object) Clone the point object. extend (items) Extends the array by appending elements. getObject (index) Returns the object at the given index position in the array. insert (index, value) Adds an object to the

Comments
  • Please use the 'name' property to compare each object in array
  • Hi! When you were asking your question, there was a big orange How to Format box to the right of the text area with useful info in it. There was also a toolbar full of formatting aids. And a [?] button giving formatting help. And a preview area showing what your post would look like when posted, located between the text area and the Post Your Question button (so that you'd have to scroll past it to find the button, to encourage you to look at it). Making your post clear, and demonstrating that you took the time to do so, improves your chances of getting good answers.
  • (I've fixed the formatting for you on this occasion.)
  • @T.J.Crowder any hope for answer?
  • Thank you that's exactly what i want :)
  • @PrazSolver - Glad to help you :)