如何在嵌套数组对象中删除和添加项目

Question

I have nested array objects which have items in it. I want to remove item from id:4 except first item and add it id:5 object.

const data = [
  {
    id: 1,
    items: [ { id:11 }, {id:12 } ],
  },
  {
    id: 2,
    items: [ { id:21 } ],
  },
  {
    id: 3,
    items: [ { id:31 } ],
  },
  {
    id: 4,
    items: [ { id:41 }, {id:42 } ],
  },
  {
    id: 5,
    items: [ { id:51 } ],
  },
]

so my resultant array should be like this

 const data = [
  {
    id: 1,
    items: [ { id:11 }, {id:12 } ],
  },
  {
    id: 2,
    items: [ { id:21 } ],
  },
  {
    id: 3,
    items: [ { id:31 } ],
  },
  {
    id: 4,
    items: [ { id:41 } ],
  },
  {
    id: 5,
    items: [ {id:42 }, { id:51 } ],
  },
]

Answer 1

I'll do it in two steps, first to get all of the items in the item with id 4 except the first one:

let moreItems = [];

data.forEach((item) => {
    if (item.id === 4) {
       
       while(item.items.length > 1) {
        moreItems.push(item.items[item.items.length-1]);
        item.items.pop();
       }
    }
});

moreItems will be the array to add to the items in the item with id 5.

data.forEach((item) => {
    if (item.id === 5) {
        if (moreItems.length > 0) {
            item.items = item.items.concat(moreItems);
        }
    }
});

Answer 2

Maybe something like this?

let v = data[3].items.pop()
data[4].items.push(v)

The question was not the most clear. If you need to do this based on some condition or logic you will have to do that yourself.

Answer 3

如果您需要从 id=4 复制所有项目，请使用以下代码： data[4].items.push(data[3].items.splice(1,data[3].items.length));