Combine values from different objects in same array - javascript

Question

i have an array that looks like this:

array = [{game: 1, team: aName, score: 10 },{game: 1, team: bName, score: 1}, {game: 2, team: aName, score: 20}, {game:2, team: bName, score: 30}]

i need a way to sum all the scores from the different teams so i get something like this:

sumArray = [{team:aName, score: 30},{team:bName, score:31}]

is there a way to achieve this with JS?

thanks!

"javascript group array of objects by property" (+ eventually " site:stackoverflow.com") — Andreas
– Andreas, Commented Jul 23, 2020 at 12:32

8HoLoN · Accepted Answer · 2020-07-23 12:39:38Z

1

That what you want

const array = [
    { game: 1, team: 'aName', score: 10 },
    { game: 1, team: 'bName', score: 1 },
    { game: 2, team: 'aName', score: 20 },
    { game: 2, team: 'bName', score: 30 }
]

console.log([...array.reduce((a, c) => {
    if (a.has(c.team)) {
        a.get(c.team).score += c.score;
    } else {
        a.set(c.team, c);
    }
    return a;
}, new Map()).values()])

edited Jul 23, 2020 at 12:39

answered Jul 23, 2020 at 12:33

8HoLoN

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4 Comments

Krzysztof Krzeszewski Over a year ago

the snippet logs an empty object, is that what you wanted?

Andreas Over a year ago

How does your script work? And you might want to fix the output of the iterator returned by Map.prototype.values()

Thymas1 Over a year ago

Great! Thank you!

8HoLoN Over a year ago

The result is an array now

Pedro Lima · Accepted Answer · 2020-07-23 12:37:37Z

0

Yes, there is.

array = [{game: 1, team: 'aName', score: 10 },{game: 1, team: 'bName', score: 1}, {game: 2, team: 'aName', score: 20}, {game:2, team: 'bName', score: 30}];

sumArray = array
    .map(e => e.team) // Map teams
    .filter((v, i, s) => s.indexOf(v) == i) // Getting only unique teams
    .map(t => ({ team: t, score: array.filter(e => e.team == t).reduce((p, v) => p + v.score, 0) })); // generate a reduced object for each team

console.log(sumArray);

answered Jul 23, 2020 at 12:37

Pedro Lima

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Comments

Krzysztof Krzeszewski · Accepted Answer · 2020-07-23 12:38:46Z

0

Using reduce function to gather the scores

const data = [{
  game: 1,
  team: "aName",
  score: 10
}, {
  game: 1,
  team: "bName",
  score: 1
}, {
  game: 2,
  team: "aName",
  score: 20
}, {
  game: 2,
  team: "bName",
  score: 30
}]

const result = Object.values(data.reduce((result, {team, score}) => {
  if (!result[team]) result[team] = {team, score}
  else result[team].score+=score;
  return result;
}, {}));

console.log(result)

answered Jul 23, 2020 at 12:38

Krzysztof Krzeszewski

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