对象数组中匹配键的总和

Question

Problem

I need to sum the values of matching keys in a nested array of objects. There are two sub objects inside each object. I need to sum the values of the second nest object. Your help would be greatly appreciated! I know there are other similar questions but their inputs are formatted differently so working off their examples is giving me a lot of trouble since I'm new to JS

Array to sum

It has more than two objects in the array but I only included two for brevity.

stats: [
    0: {
        statsFields: {
            duo: 2
            duoM: 2
            duoW: 2
            kdr: 2
            solo: 2
            soloM: 2
            soloW: 2
            squad: 2
            squadM: 2
            squadW: 2
            total: 2
            totalM: 1
            totalW: 2
            winP: 2
        },
        _id: "5cc283ba7b752f322ce26168"
    },
    1: {
        statsFields: {
            duo: 2
            duoM: 2
            duoW: 2
            kdr: 2
            solo: 2
            soloM: 2
            soloW: 2
            squad: 2
            squadM: 2
            squadW: 2
            total: 2
            totalM: 1
            totalW: 2
            winP: 2
        },
        _id: "5cc284cd7b752f322ce26169"
    },
]

Desired Output

statsFields: {
    duo: 4
    duoM: 4
    duoW: 4
    kdr: 4
    solo: 4
    soloM: 4
    soloW: 4
    squad: 4
    squadM: 4
    squadW: 4
    total: 4
    totalM: 2
    totalW: 4
    winP: 4
}

What I've tried

I've tried a reducer with a map and I've also tried a for loop but I'm having trouble because the object is so deeply nested in the array and there is also a second object in the array I don't need which is producing errors.

Answer 1

 let stats = [{ statsFields: { duo: 2, duoM: 2, duoW: 2, kdr: 2, solo: 2, soloM: 2, soloW: 2, squad: 2, squadM: 2, squadW: 2, total: 2, totalM: 1, totalW: 2, winP: 2, }, _id: "5cc283ba7b752f322ce26168", }, { statsFields: { duo: 2, duoM: 2, duoW: 2, kdr: 2, solo: 2, soloM: 2, soloW: 2, squad: 2, squadM: 2, squadW: 2, total: 2, totalM: 1, totalW: 2, winP: 2, }, _id: "5cc284cd7b752f322ce26169", }]; let sum = stats.reduce((acc, {statsFields}) => { Object.entries(statsFields).forEach(([key, value]) => acc[key] = (acc[key] || 0) + value); return acc; }, {}); console.log(sum); 

Answer 2

Here is how I'll do this:

 var ary = { stats: [{ statsFields: { duo: 2, duoM: 2, duoW: 2, kdr: 2, solo: 2, soloM: 2, soloW: 2, squad: 2, squadM: 2, squadW: 2, total: 2, totalM: 1, totalW: 2, winP: 2, }, _id: "5cc283ba7b752f322ce26168" }, { statsFields: { duo: 2, duoM: 2, duoW: 2, kdr: 2, solo: 2, soloM: 2, soloW: 2, squad: 2, squadM: 2, squadW: 2, total: 2, totalM: 1, totalW: 2, winP: 2, }, _id: "5cc284cd7b752f322ce26169" }, ] } var res = ary.stats.reduce((acc, cur) => { var keys = Object.keys(cur.statsFields) return keys.reduce((mem, key) => { mem[key] = (acc.statsFields[key] || 0) +( cur.statsFields[key] || 0); return mem; }, {}) }); console.log(res) 

Answer 3

If the data is from a JSON string, it can also be done during parsing :

 var result = {}, json = '{"stats":[{"statsFields":{"duo":2,"duoM":2,"duoW":2,"kdr":2,"solo":2,"soloM":2,"soloW":2,"squad":2,"squadM":2,"squadW":2,"total":2,"totalM":1,"totalW":2,"winP":2},"_id":"5cc283ba7b752f322ce26168"},{"statsFields":{"duo":2,"duoM":2,"duoW":2,"kdr":2,"solo":2,"soloM":2,"soloW":2,"squad":2,"squadM":2,"squadW":2,"total":2,"totalM":1,"totalW":2,"winP":2},"_id":"5cc284cd7b752f322ce26169"}]}' JSON.parse(json, (k, v) => v.toFixed && (result[k] = result[k] + v || v)) console.log( result )