如何比较两个对象数组，如果值相同，则添加新键：Javascript 中第二个对象的值

Question

Let's take an example. I've two array of objects

let paymentType = [
  {id: "settle", set: "dis_10"},
  {id: "settle1", set: "dis_20"},
  {id: "settle2", set: "dis_30"},
]

let result = [
  {id: "settle", type: 40},
  {id: "settle4", type: 50},
  {id: "settle2", type: 60},
]

If id from both array matches I want to add the the set value to the result array of object. Final result will be

let result = [
  {id: "settle", type: 40, set: "dis_10"},
  {id: "settle4", type: 50},
  {id: "settle2", type: 60},
]

I've tried using filter and some method, but didn't work as expected

Answer 1

I'd reduce() everything to a single accumulator object keyed by id , and then get the values from that:

 const paymentType = [ {id: "settle", set: "dis_10"}, {id: "settle1", set: "dis_20"}, {id: "settle2", set: "dis_30"}, ]; const result = [ {id: "settle", type: 40}, {id: "settle4", type: 50}, {id: "settle2", type: 60}, ]; const merge = (...arrays) => Object.values( arrays.reduce((a, array) => array.reduce((a, v) => { a[v.id] = {...(a[v.id] || {}), ...v }; return a; }, a), {}) ); console.log(merge(paymentType, result));

This has a linear runtime complexity ( O(n) ), as opposed to solutions that invoke find() or findIndex() on every iteration which are O(n log n) at best.

Answer 2

Hope it helps:

 const paymentType = [ {id: "settle", set: "dis_10"}, {id: "settle1", set: "dis_20"}, {id: "settle2", set: "dis_30"}, ]; let result = [ {id: "settle", type: 40}, {id: "settle4", type: 50}, {id: "settle2", type: 60}, ]; result.forEach((resultItem, index) => { const id = resultItem.id; // Chech if the id exists in the paymentType array const paymentTypeIndex = paymentType.findIndex((paymentTypeItem) => paymentTypeItem.id === id); if(paymentTypeIndex > -1) { // If the id exists, we add the paymentType item values to the result item. resultItem.set = paymentType[paymentTypeIndex].set; } }); console.log(result);

Answer 3

this might be something that you are looking for if I understood your question well

 result.forEach((item) => {
      if (paymentType.find((el) => el.id == item.id))
        item.set = paymentType.find((el) => el.id == item.id).set;
    });

This will result in

[
    {
        "id": "settle",
        "type": 40,
        "set": "dis_10"
    },
    {
        "id": "settle4",
        "type": 50
    },
    {
        "id": "settle2",
        "type": 60,
        "set": "dis_30"
    }
]