如果嵌套陣列不存在，則插入嵌套陣列

如果嵌套陣列中不存在，我正在嘗試插入新資料，到目前為止，如果它們不存在，我可以添加，但它正在洗掉以前的資料，任何幫助將不勝感激。

陣列

const posts = 
  [ { _id: 1
    , message: 'this is post one'
    , likes:    [ { id: 111221, user: 'random 1' } , { id: 2223422, user:'random 2' } ] 
    , comments: [ { id: 332233, message: 'random comment' } , { id: 2344444, message:'another random comment' } ] 
  }] 
const comments = 
  [ { id: 3333, message: 'this is comment 1' } 
  , { id: 4444, message: 'this is comment 2' } 
  ] 
const likes = 
  [ { id: 1111, user: 'Peter' } 
  , { id: 2222, user: 'John'  } 
  ] 

預期產出

const newPost = 
  [ { _id: 1
    , message: 'this is post one'
    , likes:    [ 
        { id: 1111, user: 'Peter' } ,
        { id: 111221, user: 'random 1' } , 
        { id: 2223422, user:'random 2' } ,
        { id: 2222, user: 'John'  }
    ] 
    , comments: [ 
        { id: 3333, message: 'this is comment 1' } ,
        { id: 4444, message: 'this is comment 2' },
        { id: 332233, message: 'random comment' } , 
        { id: 2344444, message:'another random comment' } 
    ] 
  }] 

我試過的

const newPosts = posts.map(post => ({
    ...post,
    likes: likes.filter(like => !post.likes.map(like => like.id).includes(like.id)),
    comments: comments.filter(comment => !post.comments.map(comment => comment.id).includes(comment.id)),
}))

console.log(newPosts)

uj5u.com熱心網友回復：

也許我太累了，但我只是將陣列合并在一起。你的帖子沒有提到你需要檢查變數中的評論是否comments已經存在于 posts[0].comments ( _id: 1) 中。

const posts = [{
  _id: 1,
  message: 'this is post one',
  likes: [{
    id: 111221,
    user: 'random 1'
  }, {
    id: 2223422,
    user: 'random 2'
  }],
  comments: [{
    id: 332233,
    message: 'random comment'
  }, {
    id: 2344444,
    message: 'another random comment'
  }]
}]

const comments = [{
  id: 3333,
  message: 'this is comment 1'
}, {
  id: 4444,
  message: 'this is comment 2'
}]
const likes = [{
  id: 1111,
  user: 'Peter'
}, {
  id: 2222,
  user: 'John'
}]

const addTo = (posts, comments, likes) => {
  let newPostInstance = [...posts][0];
  
  newPostInstance.comments = [...newPostInstance.comments, ...comments];
  newPostInstance.likes    = [...newPostInstance.likes, ...likes];
  
  return newPostInstance;
}

const newPost = addTo(posts, comments, likes);

console.log(newPost)

uj5u.com熱心網友回復：

const posts1 = 
  [ { _id: 1
    , message: 'this is post one'
    , likes:    [ { id: 111222221, user: 'random 1' } , { id: 2223422, user:'random 2' } ] 
    , comments: [ { id: 3322222233, message: 'random comment' } , { id: 2344444, message:'another random comment' } ] 
  }] 


  const posts = 
  [ { _id: 1
    , message: 'this is post one'
    , likes:    [ { id: 111221, user: 'random 1asdasdasd' } , { id: 2223422, user:'random 2asdasdasd' } ] 
    , comments: [ { id: 332233, message: 'rasdasdasd' } , { id: 2344444, message:'asdasdasdwwwwww' } ] 
  }] 

if(posts.filter(r => r.comments) !== posts1.filter(r => r.comments)){
    const a = posts.map(({likes,_id,message, ...o}) => ({...o.comments}))
    const b = posts1.map(({likes,_id,message, ...o}) => ({...o.comments}))
    const c = posts.map(({comments,_id,message, ...o}) => ({...o.likes}))
    const d = posts1.map(({comments,_id,message, ...o}) => ({...o.likes}))

    const newComments = [...a,...b]
    const newLikes = [...c,...d]

    const returnFlattenObject = (arr) => {
        const flatObject = {};
        for(let i=0; i<arr.length; i  ){
           for(const property in arr[i]){
              flatObject[`${property}_${i}`] = arr[i][property];
           }
        };
        return flatObject;
    }

    posts.map(({comments,likes, ...o}) => ({
        ...o,
        comments: returnFlattenObject(newComments),
        likes: returnFlattenObject(newLikes)
    }))
} else {
    console.log('exists')
}

結果

[{…}]
0:
comments:
0_0: {id: 332233, message: 'rasdasdasd'}
0_1: {id: 3322222233, message: 'random comment'}
1_0: {id: 2344444, message: 'asdasdasdwwwwww'}
1_1: {id: 2344444, message: 'another random comment'}
[[Prototype]]: Object
likes:
0_0: {id: 111221, user: 'random 1'}
0_1: {id: 111222221, user: 'random 1'}
1_0: {id: 2223422, user: 'random 2'}
1_1: {id: 2223422, user: 'random 2'}
[[Prototype]]: Object
message: "this is post one"
_id: 1
[[Prototype]]: Object
length: 1
[[Prototype]]: Array(0)

標籤：javascript

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