Question

我有这样的结构

[
    {"id": "as2is0", "replies": [{"id": "e345k2e", "replies": [. . .]} ]},
    {"id": "2ishkl8"}
] . . .

很难预测评论有多少回复。我基本上想遍历每个单独的评论，无论是回复还是顶级评论。我该怎么做呢？可能还会有其他答复，因此我的基本循环解决方案不起作用。

Answer 1

您想要的是一个递归函数，这意味着它在某些条件下会自行调用。这是一个例子

const data = [
    {
      id: "abc",
      replies: [
        {id: "def", replies: [
          {id: 'ghi', replies: [] }
        ]} 
      ]
    },
    {
      id: "jkl",
      replies: [
        {id: "mno", replies: [
          {id: 'pqr', replies: [] }
        ]} 
      ]
    }
]

function logReplies(data) {
  data.forEach(item => {
    console.log('id:', item.id);
    if (item.replies) {
      logReplies(item.replies);
    }
  });
}

logReplies(data);

文档

https://developer.mozilla.org/en-US/docs/Glossary/Recursion

Answer 2

这是一个非常简单的recursive function，只需打印ids即可入门：

const data = [{
    id: "as2is0",
    replies: [{
      id: "e345k2e",
      replies: [{
        id: "e34112e",
        replies: []
      }]
    }]
  },
  {
    "id": "2ishkl8"
  }
]

// notice the function accepts an array as a parameter
const getComments = arr => arr.forEach(x => {   // <-- for every element
  if(x.id)
    console.log(x.id)
  if(x.replies)    // <-- if there are any children
    getComments(x.replies)  // <-- call with the children array as parameter now
})

getComments(data)  // <-- do the initial call of the function

想法是通过在每个级别上调用getComments来遍历树，并一直这样做，直到不再有任何子级/答复为止。

Answer 3

如果您首先对检索扁平化的注释感兴趣，而不是在遍历该注释时直接进行处理（其他答案会指向您），则可以执行以下操作：

FileInputStream in = new FileInputStream("D:\\work\\calculatepi\\sampleresult.xlsx");
Workbook workbook = StreamingReader.builder()
    .rowCacheSize(100)  
    .bufferSize(4096)  
    .open(in);

这还将确保所有不是const comments = [ {"id": "as2is0", "replies": [{"id": "e345k2e", "replies": []} ]}, {"id": "2ishkl8"} ]; function getFlattenedComments(comments) { const flattenedComments = []; for ({replies, ...commentWithoutReplies} of comments) { flattenedComments.push(commentWithoutReplies); if (replies) { flattenedComments.push(...getFlattenedComments(replies)); } } return flattenedComments; } console.log(getFlattenedComments(comments));的属性（不仅仅是replies，如果有的话也可能包含其他属性）将保留在扁平化的集合中。

Answer 4

您将需要使用递归来解决您的问题。我不确定您要对每个答复执行什么操作，或者对每个子注释需要采取什么操作，但是在下面的代码段中，我假设您想以树状结构解析它们，并使用缩进标记它们在树中水平。

当然，您可以更改解析代码并将其替换为您需要的任何操作。

// here is my attempt at building a complex layers of nested comments
var comments = [
    {"id": "as2is0", "replies": [
                     {"id": "e345k2e", "replies": []},
                     {"id": "f12ba55", "replies": [{"id":"st123abc","replies":[{"id": "y345k2e", "replies": []}]}]} ]},
    {"id": "k345k2e", "replies": [{"id": "q96yyt", "replies": []}]},
    {"id": "2ishkl8"}
];

// begin at the outer level, parse each element separately
comments.forEach(function(c){
  console.log(parse(c));
});


// the parse function takes two parameters: the comment object and the level
function parse(c,lvl) {
   //if level is not specified, it is assumed to be root level
   if(!lvl) { lvl = 0 }
   
   // if current comment contains no replies, or empty array:
   if(!c.replies || c.replies.length==0) {
      return  c.id;   
   } else {
      // build a string to contain all nested replies
      var str = c.id + " : " ;
      // iterate through all replies of current comment
      c.replies.forEach(function(r){
        
        str +=  "\n" ;                // add a new line
        str += ("  ").repeat( lvl+1); // indent reply as depending on the level
        str += parse(r,(lvl+1));      // recursive call to parse cunction
                                      // but with one level deeper
      });
      return str;
   }
   
}

JS-如何遍历其他对象数组中的数组

4 个答案:

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