用更新的对象替换嵌套的对象数组

Question

我有两个对象数组。我想更新/替换嵌套的对象"comments"其中collection1.comments._id === collection2。

collection1: [
0:  {
"_id": "6104844e42c23e6d215651cd",
"comments": [
{
"_id": "6143e24273c10e4658852063",
"user": "6138b154e4c6a30dc5661da7",
"comment": "Beautiful Day Outside"
},
{
"_id": "6143e24673c10e4658852065",
"user": "6138b154e4c6a30dc5661da7",
"comment": "Let us go for a picnic"
},
{
"_id": "6145d58519a1d70d89512c9c",
"user": "6144eef7d01acc2a77f4219c",
"comment": "taking time to smell the flowers"
}...
]
},
1:   {
"_id": "6104842e42c23e6d215651ca",
"comments": [
{
"_id": "61472dab0224a10e11aa45f8",
"user": "6144eef7d01acc2a77f4219c",
"comment": "Baking cookies for the party"
},
{
"_id": "61472ecb9c2ece100a525c55",
"user": "6138b154e4c6a30dc5661da7",
"comment": "Listening to the waves by the shore"
}......
]
}
]
collection2: [
0:  {
"cid": "6143e24273c10e4658852063",
"uid": "6138b154e4c6a30dc5661da7",
"firstName": "mom",
"lastName": "mom",
"comment": "Beautiful Day Outsite"
},
1:  {
"cid": "6143e24673c10e4658852065",
"uid": "6138b154e4c6a30dc5661da7",
"firstName": "mom",
"lastName": "mom",
"comment": "Let us go for a picnic"
},
2:  {
"cid": "61472dab0224a10e11aa45f8",
"uid": "6144eef7d01acc2a77f4219c",
"firstName": "james",
"lastName": "james",
"comment": "Baking cookies for the party"
},
3:  {
"cid": "61472ecb9c2ece100a525c55",
"uid": "6138b154e4c6a30dc5661da7",
"firstName": "james",
"lastName": "james",
"comment": "Listening to the waves by the shore"
},
...
]

我已经尝试了地图功能:

collection1.map(obj => collection2.find(o => o.cid === obj.comments._id) || obj);

但我得到:TypeError:无法读取未定义的属性'_id'。我不知道下一步该做什么。如有任何帮助，将不胜感激。

Answer 1

const collection1 = [
{
"_id": "6104844e42c23e6d215651cd",
"comments": [
{
"_id": "6143e24273c10e4658852063",
"user": "6138b154e4c6a30dc5661da7",
"comment": "Beautiful Day Outside"
},
{
"_id": "6143e24673c10e4658852065",
"user": "6138b154e4c6a30dc5661da7",
"comment": "Let us go for a picnic"
},
{
"_id": "6145d58519a1d70d89512c9c",
"user": "6144eef7d01acc2a77f4219c",
"comment": "taking time to smell the flowers"
}
]
},

{
"_id": "6104842e42c23e6d215651ca",
"comments": [
{
"_id": "61472dab0224a10e11aa45f8",
"user": "6144eef7d01acc2a77f4219c",
"comment": "Baking cookies for the party"
},
{
"_id": "61472ecb9c2ece100a525c55",
"user": "6138b154e4c6a30dc5661da7",
"comment": "Listening to the waves by the shore"
}
]
}
]
const collection2 = [
{
"cid": "6143e24273c10e4658852063",
"uid": "6138b154e4c6a30dc5661da7",
"firstName": "mom",
"lastName": "mom",
"comment": "Beautiful Day Outsite"
},
{
"cid": "6143e24673c10e4658852065",
"uid": "6138b154e4c6a30dc5661da7",
"firstName": "mom",
"lastName": "mom",
"comment": "Let us go for a picnic"
},
{
"cid": "61472dab0224a10e11aa45f8",
"uid": "6144eef7d01acc2a77f4219c",
"firstName": "james",
"lastName": "james",
"comment": "Baking cookies for the party"
},
{
"cid": "61472ecb9c2ece100a525c55",
"uid": "6138b154e4c6a30dc5661da7",
"firstName": "james",
"lastName": "james",
"comment": "Listening to the waves by the shore"
}
]

const updatedCollection1 = collection1.map(col1 => {
const updatedComments = col1.comments.map((col1_comment => {
const matched_comment = collection2.find(el => el.cid === col1_comment._id)
return matched_comment
}))
return {...col1, comments: updatedComments}
})
console.log(updatedCollection1)

Array.prototype.map()方法可以如下:

const updatedCollection1 = collection1.map(col1 => {
const updatedComments = col1.comments.map((col1_comment => {
const matched_comment = collection2.find(el => el.cid === col1_comment._id)
return matched_comment
}))
return {...col1, comments: updatedComments}
})

Answer 2

这是相对容易实现的递归函数，使用Object.entries在您的源代码，并尝试分配值"并行";致你的目标:

function setDataFrom(source, target) {
for (const [key, val] of Object.entries(source)) {
if (val !== null && typeof val === `object`) {
if (target[key] === undefined) {
target[key] = {};
}
setDataFrom(val, target[key]);
} else {
target[key] = val;
}
}
return target;
}

这也可以让你免费获得深度拷贝:

function copyFromSource(source) {
return setDataFrom(source, {});
}

Answer 3

您可以通过注释map并使用find来检查id的匹配位置。

const collection1 = [{
"_id": "6104844e42c23e6d215651cd",
"comments": [{
"_id": "6143e24273c10e4658852063",
"user": "6138b154e4c6a30dc5661da7",
"comment": "Beautiful Day Outside"
},
{
"_id": "6143e24673c10e4658852065",
"user": "6138b154e4c6a30dc5661da7",
"comment": "Let us go for a picnic"
},
{
"_id": "6145d58519a1d70d89512c9c",
"user": "6144eef7d01acc2a77f4219c",
"comment": "taking time to smell the flowers"
}
]
},
{
"_id": "6104842e42c23e6d215651ca",
"comments": [{
"_id": "61472dab0224a10e11aa45f8",
"user": "6144eef7d01acc2a77f4219c",
"comment": "Baking cookies for the party"
},
{
"_id": "61472ecb9c2ece100a525c55",
"user": "6138b154e4c6a30dc5661da7",
"comment": "Listening to the waves by the shore"
}
]
}
]
const collection2 = [{
"cid": "6143e24273c10e4658852063",
"uid": "6138b154e4c6a30dc5661da7",
"firstName": "mom",
"lastName": "mom",
"comment": "Beautiful Day Outsite"
},
{
"cid": "6143e24673c10e4658852065",
"uid": "6138b154e4c6a30dc5661da7",
"firstName": "mom",
"lastName": "mom",
"comment": "Let us go for a picnic"
},
{
"cid": "61472dab0224a10e11aa45f8",
"uid": "6144eef7d01acc2a77f4219c",
"firstName": "james",
"lastName": "james",
"comment": "Baking cookies for the party"
},
{
"cid": "61472ecb9c2ece100a525c55",
"uid": "6138b154e4c6a30dc5661da7",
"firstName": "james",
"lastName": "james",
"comment": "Listening to the waves by the shore"
},
]
const result = collection1.flatMap((c) => c.comments).map((c) => {
return {
commentPart1: c,
commentPart2: collection2.find((x) => x.cid === c._id)
}
});
console.log(result);