如何对相同键的值求和并在每个对象的对象数组中添加一个键，该键的值包含 id 相同键的数组？

Question

I have an array that contains these objects. What I want is sum values with same key and add a key contains id same keys that were match toghther. For example,

var data = [ 
     {id:1, name: "fieldA", value: 20, },
     {id:2, name: "building", value: 20, },
     {id:3, name: "fieldA", value: 20, },
     {id:4, name: "building", value: 20, }
    ];

have to become something like it:

var data = [
 {id:1,idd:[1,3], name: "fieldA", value: 40, },
 {id:2,idd:[2,4], name: "building", value: 40, },
];

i have used this code: but i cant reach what i told above! :

var data = [ {id:1,id2:[], name: "fieldA", value: 20, }, {id:2,id2:[], name: "building", value: 20, }, {id:3,id2:[], name: "fieldA", value: 20, }, {id:4,id2:[], name: "building", value: 20, }];

var result = Object.values(data.reduce((acc,{id,id2, name, value})=>{
    acc[name] = acc[name] || {id,id2, name, value:0};
    acc[name].value +=value;
    acc[name].id2[id2.length]= acc[name].id
/*     console.log(acc[name])
     */        return acc;
},{}));

console.log(result);

i decide use reduce and map as it can. thanks.

note: this code has inspired from this question:

check array of objects if have same key and sum value

Answer 1

All you need to do is push the correct id , which you have already extracted using destructuring.

Also since you do not want to add the individual value s, you can just omit the + sign to have the last value .

 var data = [ {id:1,id2:[], name: "fieldA", value: 20, }, {id:2,id2:[], name: "building", value: 20, }, {id:3,id2:[], name: "fieldA", value: 20, }, {id:4,id2:[], name: "building", value: 20, }]; var result = Object.values(data.reduce((acc,{id,id2, name, value})=>{ acc[name] = acc[name] || {id,id2, name, value:0}; acc[name].value += value; acc[name].id2.push(id); return acc; },{})); console.log(result);

Answer 2

Use array.reduce in javascript.

Just parse the accumulator array to find the node with combination of name and value. If that combination is not found, push the current node with id of current node in idd key. Or else push the id of current node to the idd key of node from the accumulator array.

 var data = [ {id:1, name: "fieldA", value: 20, }, {id:2, name: "building", value: 20, }, {id:3, name: "fieldA", value: 20, }, {id:4, name: "building", value: 20, } ]; const output = data.reduce((acc, curr) => { const node = acc.find((item) => item.name === curr.name && item.value === curr.value); if (node) { node.idd.push(curr.id); node.value += curr.value; } else { acc.push({ ...curr, idd: [curr.id]}) } return acc; }, []); console.log(output)

Answer 3

it looks like you just need to replace your line

acc[name].id2[id2.length]= acc[name].id

with

acc[name].id2.push(id)

So this:

var data = [ 
    {id:1,id2:[], name: "fieldA", value: 1, }, 
    {id:2,id2:[], name: "building", value: 5, }, 
    {id:3,id2:[], name: "fieldA", value: 21, }, 
    {id:4,id2:[], name: "building", value: 85, }
];

var result = Object.values(data.reduce((acc,{id,id2, name, value})=>{
    acc[name] = acc[name] || {id,id2, name, value:0};
    acc[name].value +=value;
    acc[name].id2.push(id)
    return acc;
},{}));

console.log(result);

will output:

[
    { id: 1, id2: [ 1, 3 ], name: 'fieldA', value: 22 },
    { id: 2, id2: [ 2, 4 ], name: 'building', value: 90 }
]