Reduce array of objects by user_id and sum certain values

Question

I have an array of objects that looks like this:

\"data\": [
{ \"workout_id\": 1, \"user_id\": 1, \"shotLocation\": 27, \"shotAttempts\": 20,\"shotsMade\": 19,          


        

Answer 1

const data = [
  { workout_id: 1, user_id: 1, shotLocation: 27, shotAttempts: 20, shotsMade: 19, id: 1 },
  { workout_id: 2, user_id: 1, shotLocation: 1, shotAttempts: 10, shotsMade: 9, id: 2 },
  { workout_id: 2, user_id: 1, shotLocation: 10, shotAttempts: 10, shotsMade: 7, id: 3 },
  { workout_id: 2, user_id: 1, shotLocation: 1, shotAttempts: 30, shotsMade: 29, id: 4 },
  { workout_id: 3, user_id: 5, shotLocation: 1, shotAttempts: 10, shotsMade: 9, id: 5 },
  { workout_id: 4, user_id: 6, shotLocation: 1, shotAttempts: 30, shotsMade: 15, id: 6 },
  { workout_id: 4, user_id: 6, shotLocation: 2, shotAttempts: 20, shotsMade: 14, id: 7 }
];

const shooters = data.reduce(
  (results, current) => ({
    ...results,
    [current.user_id]: {
      user_id: current.user_id,
      shotAttempts: current.shotAttempts + (results[current.user_id] ? results[current.user_id].shotAttempts : 0),
      shotsMade: current.shotsMade + (results[current.user_id] ? results[current.user_id].shotsMade : 0)
    }
  }),
  {}
);

console.log(shooters);

Answer 2

You can use Array.reduce, Object.values with ES6 destructuring and solve this in a concise manner:

const data = [{ "workout_id": 1, "user_id": 1, "shotLocation": 27, "shotAttempts": 20, "shotsMade": 19, "id": 1 }, { "workout_id": 2, "user_id": 1, "shotLocation": 1, "shotAttempts": 10, "shotsMade": 9, "id": 2 }, { "workout_id": 2, "user_id": 1, "shotLocation": 10, "shotAttempts": 10, "shotsMade": 7, "id": 3 }, { "workout_id": 2, "user_id": 1, "shotLocation": 1, "shotAttempts": 30, "shotsMade": 29, "id": 4 }, { "workout_id": 3, "user_id": 5, "shotLocation": 1, "shotAttempts": 10, "shotsMade": 9, "id": 5 }, { "workout_id": 4, "user_id": 6, "shotLocation": 1, "shotAttempts": 30, "shotsMade": 15, "id": 6 }, { "workout_id": 4, "user_id": 6, "shotLocation": 2, "shotAttempts": 20, "shotsMade": 14, "id": 7 } ]

const result = data.reduce((r,{workout_id, user_id, shotAttempts, shotsMade}) => {
 r[user_id] = r[user_id] || {id: workout_id, user_id, shotAttempts: 0, shotsMade: 0}
 r[user_id].shotAttempts += shotAttempts
 r[user_id].shotsMade += shotsMade
 return r
}, {})

console.log(Object.values(result))

Answer 3

You can use Array.prototype.reduce()

Code:

const data = [{ "workout_id": 1, "user_id": 1, "shotLocation": 27, "shotAttempts": 20,"shotsMade": 19, "id": 1 },{ "workout_id": 2, "user_id": 1, "shotLocation": 1, "shotAttempts": 10, "shotsMade": 9, "id": 2 },{ "workout_id": 2, "user_id": 1, "shotLocation": 10, "shotAttempts": 10, "shotsMade": 7, "id": 3 },{ "workout_id": 2, "user_id": 1, "shotLocation": 1, "shotAttempts": 30, "shotsMade": 29, "id": 4 },{ "workout_id": 3, "user_id": 5, "shotLocation": 1, "shotAttempts": 10, "shotsMade": 9, "id": 5 },{ "workout_id": 4, "user_id": 6, "shotLocation": 1, "shotAttempts": 30, "shotsMade": 15, "id": 6 },{ "workout_id": 4, "user_id": 6, "shotLocation": 2, "shotAttempts": 20, "shotsMade": 14, "id": 7 }];
const dataTotals = Object.values(data.reduce((a, c) => {
  if (!a[c.user_id]) {
    a[c.user_id] = {
      id: c.workout_id,
      user_id: c.user_id,
      shotAttempts: c.shotAttempts,
      shotsMade: c.shotsMade
    };
  } else {  
    a[c.user_id].shotAttempts += c.shotAttempts;
    a[c.user_id].shotsMade += c.shotsMade;
  }
  return a;
}, {}));

console.log(dataTotals);