SUM AND GROUPING JSON DATA USING JAVASCRIPT

Sorry if this has been asked before, but I couldn’t find a good example of what I’m trying to accomplish. Maybe I’m just not searching for the right thing. Please correct me if there’s an explanation of this somewhere.

so let’s says I have a data like this :

data = [
{"no":1,"location":"New York","transaction":3000},
{"no":2,"location":"Tokyo","transaction":3000},
{"no":3,"location":"New York","transaction":3000},
{"no":4,"location":"Amsterdam","transaction":3000},
{"no":5,"location":"Manchester","transaction":3000},
{"no":6,"location":"New York","transaction":3000},
{"no":7,"location":"Tokyo","transaction":3000},
{"no":8,"location":"Tokyo","transaction":3000},
{"no":9,"location":"New York","transaction":3000},
{"no":10,"location":"Amsterdam","transaction":3000}
]

what i wanted to is an output like this :

result = [
{"location":"New York","transaction":12000},
{"location":"Tokyo","transaction":9000},
{"location":"Amsterdam","transaction":6000}
{"location":"Manchester","transaction":3000}
]

so what i wanted to do is grouping the data based on location and sum the transaction where the location is same and push the data to another array. i don’t know where to start, need some help to solve this or any suggestion to solve this using Javascript. thank you

>Solution :

Working Demo :

// Input array
const data = [
{"no":1,"location":"New York","transaction":3000},
{"no":2,"location":"Tokyo","transaction":3000},
{"no":3,"location":"New York","transaction":3000},
{"no":4,"location":"Amsterdam","transaction":3000},
{"no":5,"location":"Manchester","transaction":3000},
{"no":6,"location":"New York","transaction":3000},
{"no":7,"location":"Tokyo","transaction":3000},
{"no":8,"location":"Tokyo","transaction":3000},
{"no":9,"location":"New York","transaction":3000},
{"no":10,"location":"Amsterdam","transaction":3000}
];

// result array
const resultArr = [];

// grouping by location and resulting with an object using Array.reduce() method
const groupByLocation = data.reduce((group, item) => {
  const { location } = item;
  group[location] = group[location] ?? [];
  group[location].push(item.transaction);
  return group;
}, {});

// Finally calculating the sum based on the location array we have.
Object.keys(groupByLocation).forEach((item) => {
    groupByLocation[item] = groupByLocation[item].reduce((a, b) => a + b);
    resultArr.push({
        'location': item,
      'transaction': groupByLocation[item]
    })
})

console.log(resultArr)