如何用angular中的另一个数组的子对象创建一个数组

Question

嗨伙计们，我真的被困在这里，

我正在创建一个具有子评论功能的基本评论评级系统

正如你在注释中看到的那样>“子注释”条目是对象，我想用它们创建数组，但我不知道如何因为它们在一个数组中。

我试过这个：

    this.CommentsArray.forEach((item, i) => {


  if([item]["subcomments"] != undefined) {

     [item]["subcomments"].forEach((subitem, i) => {

        subitem = this.subCommentsArray[i];
    }) 



  }

但它不起作用。有什么建议 ？

谢谢..

编辑：

我的数据结构是这样的：

"comments" : {
        "d4894e47181e43b7a0fb8b7699" : {
          "commentDate" : "2018-08-13T19:49:49.814Z",
          "commentPhotoExistence" : false,
          "commentRate" : "3",
          "commentRateState" : false,
          "commentTagState" : false,
          "commentText" : "",
          "commentUID" : "d4894e47181e43b7a0fb8b7699",
          "commenterUID" : "17QYQbhmyQeIYocIZBwH8R7ojhg1",
          "commenterUsername" : "Test2",
          "subcomments" : {
            "7c9f985d39334573b0211d18f1" : {
              "subcommentDate" : "2018-09-01T11:57:10.523Z",
              "subcommentText" : "EXAMPLE TEXT1",
              "subcommentUID" : "7c9f985d39334573b0211d18f1",
              "subcommenterUID" : "17QYQbhmyQeIYocIZBwH8R7ojhg1",
              "subcommenterUsername" : "Test2"
            },
            "a1197fb32eae483ba8e910a748" : {
              "subcommentDate" : "2018-09-01T11:29:57.514Z",
              "subcommentText" : "EXAMPLE TEST 2",
              "subcommentUID" : "a1197fb32eae483ba8e910a748",
              "subcommenterUID" : "17QYQbhmyQeIYocIZBwH8R7ojhg1",
              "subcommenterUsername" : "Test2"
            },
            "ad648a09a67c431c821bf8f290" : {
              "subcommentDate" : "2018-09-01T11:57:01.452Z",
              "subcommentText" : "example3",
              "subcommentUID" : "ad648a09a67c431c821bf8f290",
              "subcommenterUID" : "17QYQbhmyQeIYocIZBwH8R7ojhg1",
              "subcommenterUsername" : "Test2"
            },
            "f7682639d4584642a18a9a4ad7" : {
              "subcommentDate" : "2018-09-02T15:41:38.162Z",
              "subcommentText" : "example4",
              "subcommentUID" : "f7682639d4584642a18a9a4ad7",
              "subcommenterUID" : "17QYQbhmyQeIYocIZBwH8R7ojhg1",
              "subcommenterUsername" : "Test2"
            }
          }
        }

这里的问题是随机添加了子评论ID。通常如果它是Array我可以使用.forEach来使用每个项目但是在子注释和子注释属性之间有随机uid。所以我想要的是创建一个包含它们的数组，数组就像;

0: {                   "subcommentDate" : "2018-09-01T11:57:01.452Z",
                  "subcommentText" : "example3",
                  "subcommentUID" : "ad648a09a67c431c821bf8f290",
                  "subcommenterUID" : "17QYQbhmyQeIYocIZBwH8R7ojhg1",
                  "subcommenterUsername" : "Test2" 
}
1: {
                  "subcommentDate" : "2018-09-01T11:57:01.452Z",
                  "subcommentText" : "example3",
                  "subcommentUID" : "ad648a09a67c431c821bf8f290",
                  "subcommenterUID" : "17QYQbhmyQeIYocIZBwH8R7ojhg1",
                  "subcommenterUsername" : "Test2" 
}

2: {
                  "subcommentDate" : "2018-09-01T11:57:01.452Z",
                  "subcommentText" : "example3",
                  "subcommentUID" : "ad648a09a67c431c821bf8f290",
                  "subcommenterUID" : "17QYQbhmyQeIYocIZBwH8R7ojhg1",
                  "subcommenterUsername" : "Test2" 
}

等等

Answer 1

你的代码遮蔽了变量i。

你正在使用的是你的第一行this.CommentsArray.forEach((item, i) => {然后再次在subcomments。

this.CommentsArray.forEach((item, i) => {
  if([item]["subcomments"] != undefined) {
    [item]["subcomments"].forEach((subitem, z) => {
      subitem = this.subCommentsArray[z];
    }) 
  }
});

但这不是真正的问题。你试图迭代一个对象，而不是一个数组。结果将会回归;

{
  "d48...669": {
    "commentDate": '2019-08-13',
    "subcomments": {
      "7c9...8f1": {

      },
      "a11...748": {

      }
    }
  }
}

你应该按对象的键进行迭代;

Object.keys(this.CommentsArray).forEach(commentId => {
  const comment = this.CommentsArray[commentId];

  Object.keys(comment['subcomments']).forEach(subCommentId => {
    const subComment = comment['subcomments'][subCommentId];
  )};
});