如何合並來自兩個 arrays 的對象

Question

我有兩個 arrays 對象

    let current = [
        {
            categoryId: 18,
            id: 'fire_18',
            test: 'test'
        }, {
            oldItem: "items that dont exist in new array should be deleted"
        }
    ]

    let new_data = [
        {
            id: 'fire_18',
            categoryId: 18,
            test1: 'test1',
        }, {
            newItem: "new items should be added to final"
        }
    ]

我需要合並它們，這樣結果就不會丟失current數組中的數據。 期望的結果看起來像這樣

    [
        {
            id: 'fire_18',
            categoryId: 18,
            test1: 'test1',
            test: 'test'
        }, {
            newItem: "new items should be added to final"
        }
    ]

這是我的嘗試

 let current = [ { categoryId: 18, id: 'fire_18', test: 'test' }, { oldItem: "items that dont exist in new array should be deleted" } ] let new_data = [ { id: 'fire_18', categoryId: 18, test1: 'test1', }, { newItem: "new items should be added to final" } ] console.log(' === Current ==>', current); console.log(' === New ==>', new_data); new_data.map(newItem => { let currentMatch; try { // incase new item newItem.categoryId wont exist currentMatch = current.find(c => c.categoryId == newItem.categoryId) || {}; } catch (error) { // in that case, no need to merge currentMatch = {}; } return Object.assign(currentMatch, newItem); }); console.log(' === Merged ==>', new_data);

主要的錯誤仍然是合並后缺少current arr 的test密鑰。

任何人都可以修改筆以不從current arr 中刪除鍵嗎？

Answer 1

請注意， Array.map方法返回一個新數組。 您沒有記錄這個合並的新陣列 - 而是您的舊 arrays 之一。

此外，您不需要在這里try catch 。 您可能還注意到，如果categoryId未定義，對象仍將匹配。 所以，你需要檢查一下。

 let current = [ { categoryId: 18, id: 'fire_18', test: 'test' }, { oldItem: "items that dont exist in new array should be deleted" } ] let new_data = [ { id: 'fire_18', categoryId: 18, test1: 'test1', }, { newItem: "new items should be added to final" } ] newArray = new_data.map(newItem => { let currentMatch; currentMatch = current.find(c => c.categoryId === newItem.categoryId && newItem.categoryId) || {}; return Object.assign(currentMatch, newItem); }); console.log(' === Merged ==>', newArray);

Answer 2

您可以為此使用 lodash。

finalArr = _(_.flatten([current, new_data]))
                                        .groupBy('id')
                                        .map(_.spread(_.assign))
                                        .value();

Answer 3

像這樣？ 我不確定您期望newItem和oldItem條目會發生什么。

 let current = [{ categoryId: 18, id: 'fire_18', test: 'test' }] let new_data = [{ id: 'fire_18', categoryId: 18, test1: 'test1', }] const result = Object.values([...current, ...new_data].reduce((acc, { categoryId, ...other }) => ({...acc, [categoryId]: { categoryId, ...other } }), {})); console.log(result);

Answer 4

您可以使用 es6 擴展運算符來滿足您的要求

  var current = [{
    categoryId: 18,
    id: 'fire_18',
    name: 'Servers',
    slugName: 'fire_18',
    test: 'test'
}]

var new_data = [{
    id: 'fire_18',
    categoryId: 18,
    name: 'Servers',
    slugName: 'fire_18'
}]

const results = new_data.map(item => {
    let newItem = { ...item };
    const currentMatchItem = current.find(c => c.categoryId == newItem.categoryId);

    if (currentMatchItem) {
        newItem = { ...currentMatchItem, ...newItem };
    }

    return newItem;
});

console.log(results);

Answer 5

我找到了這個。 在你的代碼上是這樣的：

 let current = [ { categoryId: 18, id: 'fire_18', test: 'test' }, { oldItem: "items that dont exist in new array should be deleted" } ] let new_data = [ { id: 'fire_18', categoryId: 18, test1: 'test1', }, { newItem: "new items should be added to final" } ] function merge(a, b, prop){ var reduced = a.filter(function(aitem){ return. b;find(function(bitem){ return aitem[prop] === bitem[prop]; }); }). return reduced;concat(b). } console,log(merge(current, new_data; "id") );