如果ID在其他数组中存在，则更新/添加/删除数组中的对象 [英] Update/add/remove object in array if exist in other array by id

问题描述

我在我的有角度的应用程序中有一个项目数组(对象的有序数组).这些项目正在更新，新值来自服务(故障).我需要编写一种算法来更新现有阵列.我曾经只是用新的阵列替换旧的阵列，但是这弄乱了项目的顺序.我有以下几种极端情况，其中 oldArr 是我的旧商品数组， newArr 是来自服务的数组和 output ，如何 oldArray 应该看起来像:

I have in my angular app an array of items (ordered array of objects). Those items are getting updated and the new values are coming from a service (out of order). I need to write an algorithm to update the existing array. I used to just replace the old array with the new one, but this messed up the order of items. I have the following edge cases, where oldArr is my old array of items, the newArr is the array comming from service and the output, how the oldArray should look like:

const oldArr = [{id: 1, invalid: true}];
const newArr = [{id: 1, invalid: false}];
Output: [{id: 1, invalid: false}]

const oldArr = [{id: 1, invalid: true}];
const newArr = [{id: 1, invalid: true}, {id: 2, invalid: true}];
Output: [{id: 1, invalid: true}, {id: 2, invalid: true}]

const oldArr = [{id: 1, invalid: true}, {id: 2, invalid: true}];
const newArr = [{id: 1, invalid: true}];
Output: [{id: 1, invalid: true}]

const oldArr = [{id: 1, invalid: true}, {id: 2, invalid: true}];
const newArr = [{id: 2, invalid: true}, {id: 1, invalid: true}];
Output: [{id: 1, invalid: true}, {id: 2, invalid: true}]

const oldArr = undefined
const newArr = [{id: 1, invalid: true}, {id: 2, invalid: true}];
Output: [{id: 1, invalid: true}, {id: 2, invalid: true}]

const oldArr = [{id: 1, invalid: true}];
const newArr = undefined;
Output: undefined

const oldArr = [{id: 65, invalid: true}, {id: 2, invalid: true}];
const newArr = [{id: 2, invalid: true}, {id: 65, invalid: true}];
Output: [{id: 65, invalid: true}, {id: 2, invalid: true}]

对于这种东西，我通常使用lodash，但它也可以是普通的JS.

For this kind of stuff I usually use lodash, but it can be a plain JS as well.

推荐答案

有关:

const output = newArray.sort((a, b) => a.id - b.id);

编辑

按照提供的说明，我研究了该算法，该算法似乎产生了预期的结果

Following the clarifications provided, I worked on this algorithm which seems to produce the expected result

function merge(oldArray, newArray) {
    if(!Array.isArray(newArray)) {
        return newArray;
    }
    if(!Array.isArray(oldArray)) {
        return newArray;
    }
    //Find values that are in newArr but not in oldArr
    var diff = newArr.filter(function(obj) {
        return !oldArray.some(function(obj2) {
            return obj.id == obj2.id;
        });
    });
    // Compare elements and replace matches 
    for(let i = 0; i < oldArray.length; i += 1) {
        for(let j = 0; j < newArray.length; j += 1) {
        if(oldArray[i].id === newArray[j].id) { // Replace content if ids match
            oldArray[i] = {...newArray[j]}
            break;
        } else if(j === newArray.length -1) { // If oldArray[i] doesnt match anything in newArray, delete it
            oldArray.splice(i, 1);
            i -= 1;
        }
        }
    }
    return oldArray.concat(diff);
}

let oldArr = [{id: 1, invalid: true}];
let newArr = [{id: 1, invalid: false}];
let output = merge(oldArr, newArr)
console.log('output 1', output)


oldArr = [{id: 1, invalid: true}];
newArr = [{id: 1, invalid: true}, {id: 2, invalid: true}];
output = merge(oldArr, newArr)
console.log('output 2', output)


oldArr = [{id: 1, invalid: true}, {id: 2, invalid: true}];
newArr = [{id: 1, invalid: true}];
output = merge(oldArr, newArr)
console.log('output 3', output)

oldArr = [{id: 1, invalid: true}, {id: 2, invalid: true}];
newArr = [{id: 2, invalid: true}, {id: 1, invalid: true}];
output = merge(oldArr, newArr)
console.log('output 4', output)

oldArr = undefined
newArr = [{id: 1, invalid: true}, {id: 2, invalid: true}];
output = merge(oldArr, newArr)
console.log('output 5', output)

oldArr = [{id: 1, invalid: true}];
newArr = undefined;
output = merge(oldArr, newArr)
console.log('output 6', output)

oldArr = [{id: 65, invalid: true}, {id: 2, invalid: true}];
newArr = [{id: 2, invalid: true}, {id: 65, invalid: true}];
output = merge(oldArr, newArr)
console.log('output 7', output)

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