javascript - 如何扁平化reddit评论数据结构？

Question

我正在尝试使用 normalise api 来展平 reddit 评论数据结构。

例如下面的调用:

https://www.reddit.com/r/reactjs/comments/506gca/what_backend_and_db_are_you_using_with_react/.json

会给你嵌套结构。看起来像下面这样:

[{
          "kind": "t1",
          "data": {
            "subreddit_id": "t5_2zldd",
            "banned_by": null,
            "removal_reason": null,
            "link_id": "t3_506gca",
            "likes": null,
            "replies": {
              "kind": "Listing",
              "data": {
                "modhash": "",
                "children": [
                  {
                    "kind": "t1",
                    "data": {
                      "subreddit_id": "t5_2zldd",
                      "banned_by": null,
                      "removal_reason": null,
                      "link_id": "t3_506gca",
                      "likes": null,
                      "replies": {
                        "kind": "Listing",
                        "data": {
                          "modhash": "",
                          "children": [
                            {
                              "kind": "t1",
                              "data": {
                                "subreddit_id": "t5_2zldd",
                                "banned_by": null,
                                "removal_reason": null,
                                "link_id": "t3_506gca",
                                "likes": null,
                                "replies": {
                                  "kind": "Listing",
                                  "data": {
                                    "modhash": "",
                                    "children": [
                                      {
                                        "kind": "t1",
                                        "data": {
                                          "subreddit_id": "t5_2zldd",
                                          "banned_by": null,
                                          "removal_reason": null,
                                          "link_id": "t3_506gca",
                                          "likes": null,
                                          "replies": "",
                                          "user_reports": [],
                                          "saved": false,
                                          "id": "d724wpm",
                                          "gilded": 0,
                                          "archived": false,
                                          "report_reasons": null,
                                          "author": "bbennett36",
                                          "parent_id": "t1_d724qxh",
                                          "score": 7,
                                          "approved_by": null,
                                          "controversiality": 0,
                                          "body": "I don't think everyone here is only doing front-end lol",
                                          "edited": false,
                                          "author_flair_css_class": null,
                                          "downs": 0,
                                          "body_html": "<div class=\"md\"><p>I don't think everyone here is only doing front-end lol</p>\n</div>",
                                          "subreddit": "reactjs",
                                          "name": "t1_d724wpm",
                                          "score_hidden": false,
                                          "stickied": false,
                                          "created": 1472554709,
                                          "author_flair_text": null,
                                          "created_utc": 1472525909,
                                          "distinguished": null,
                                          "mod_reports": [],
                                          "num_reports": null,
                                          "ups": 7
                                        }
                                      }
                                    ],
                                    "after": null,
                                    "before": null
                                  }
                                },
                                "user_reports": [],
                                "saved": false,
                                "id": "d724qxh",
                                "gilded": 0,
                                "archived": false,
                                "report_reasons": null,
                                "author": "nicholasxuu",
                                "parent_id": "t1_d71oyfk",
                                "score": -10,
                                "approved_by": null,
                                "controversiality": 0,
                                "body": "why even bother asking on this sub? asking front-end experts what backend stack they like.",
                                "edited": false,
                                "author_flair_css_class": null,
                                "downs": 0,
                                "body_html": "<div class=\"md\"><p>why even bother asking on this sub? asking front-end experts what backend stack they like.</p>\n</div>",
                                "subreddit": "reactjs",
                                "name": "t1_d724qxh",
                                "score_hidden": false,
                                "stickied": false,
                                "created": 1472554467,
                                "author_flair_text": null,
                                "created_utc": 1472525667,
                                "distinguished": null,
                                "mod_reports": [],
                                "num_reports": null,
                                "ups": -10
                              }
                            }
                          ],
                          "after": null,
                          "before": null
                        }
                      },
                      "user_reports": [],
                      "saved": false,
                      "id": "d71oyfk",
                      "gilded": 0,
                      "archived": false,
                      "report_reasons": null,
                      "author": "bbennett36",
                      "parent_id": "t1_d71nyho",
                      "score": 5,
                      "approved_by": null,
                      "controversiality": 0,
                      "body": "I just want to see what stacks people are using out there.",
                      "edited": false,
                      "author_flair_css_class": null,
                      "downs": 0,
                      "body_html": "<div class=\"md\"><p>I just want to see what stacks people are using out there.</p>\n</div>",
                      "subreddit": "reactjs",
                      "name": "t1_d71oyfk",
                      "score_hidden": false,
                      "stickied": false,
                      "created": 1472531897,
                      "author_flair_text": null,
                      "created_utc": 1472503097,
                      "distinguished": null,
                      "mod_reports": [],
                      "num_reports": null,
                      "ups": 5
                    }
                  },
                  {
                    "kind": "t1",
                    "data": {
                      "subreddit_id": "t5_2zldd",
                      "banned_by": null,
                      "removal_reason": null,
                      "link_id": "t3_506gca",
                      "likes": null,
                      "replies": "",
                      "user_reports": [],
                      "saved": false,
                      "id": "d720vlw",
                      "gilded": 0,
                      "archived": false,
                      "report_reasons": null,
                      "author": "zorlan",
                      "parent_id": "t1_d71nyho",
                      "score": 1,
                      "approved_by": null,
                      "controversiality": 0,
                      "body": "This. The database should be so far removed that it doesn't affect React one iota. I would even go so far as to say this post is off topic. ",
                      "edited": false,
                      "author_flair_css_class": null,
                      "downs": 0,
                      "body_html": "<div class=\"md\"><p>This. The database should be so far removed that it doesn't affect React one iota. I would even go so far as to say this post is off topic. </p>\n</div>",
                      "subreddit": "reactjs",
                      "name": "t1_d720vlw",
                      "score_hidden": false,
                      "stickied": false,
                      "created": 1472548717,
                      "author_flair_text": null,
                      "created_utc": 1472519917,
                      "distinguished": null,
                      "mod_reports": [],
                      "num_reports": null,
                      "ups": 1
                    }
                  }
                ],
                "after": null,
                "before": null
              }
            },
            "user_reports": [],
            "saved": false,
            "id": "d71nyho",
            "gilded": 0,
            "archived": false,
            "report_reasons": null,
            "author": "shanestillwell",
            "parent_id": "t3_506gca",
            "score": 6,
            "approved_by": null,
            "controversiality": 0,
            "body": "Why does it matter? React should be a few layers removed from any database and it's quite agnostic about the backend. Heck, React itself doesn't even know how to talk to the backend. ",
            "edited": false,
            "author_flair_css_class": null,
            "downs": 0,
            "body_html": "<div class=\"md\"><p>Why does it matter? React should be a few layers removed from any database and it's quite agnostic about the backend. Heck, React itself doesn't even know how to talk to the backend. </p>\n</div>",
            "subreddit": "reactjs",
            "name": "t1_d71nyho",
            "score_hidden": false,
            "stickied": false,
            "created": 1472530637,
            "author_flair_text": null,
            "created_utc": 1472501837,
            "distinguished": null,
            "mod_reports": [],
            "num_reports": null,
            "ups": 6
          }
        }, {...},{...}]

准确地说，data.children 数组有 replies 键，它又可以有 data，它又可以有 replies等等。

我想看看如何展平这个递归结构；在更新 replies 时，在 reducer 中正确导航结构变得困难。 (在显示时，它很容易，因为您可以即时导航)

任何帮助都会很棒!

Answer 1

我不熟悉 reddit API，但是这样的东西怎么样？

// this should be handled more explicitly
function normalize( input ) {
  if( input.data ) return normalize( input.data );
  if( input.children ) return normalize( input.children );
  return input;
}

function build( input ) {
  const result = {};
  if( input.replies ) {
    input.replies = normalize( input.replies ).map( ( data ) => {
      const reply = normalize( data );
      Object.assign( result, build( reply ) );
      return reply.id;
    } );
  }
  result[ input.id ] = input;
  return result;
}

如果您的示例存储在 x 中，build( normalize( x[0] ) ); 应该给您:

{
  "d724wpm": {
    // ...
    "replies": "",
    // ...
    "id": "d724wpm",
    // ...
    "body": "I don't think everyone here is only doing front-end lol"
    // ...
  },
  "d724qxh": {
    // ...
    "replies": [
      "d724wpm"
    ],
    // ...
    "id": "d724qxh",
    // ...
    "body": "why even bother asking on this sub? asking front-end experts what backend stack they like."
    // ...
  },
  "d71oyfk": {
    // ...
    "replies": [
      "d724qxh"
    ],
    // ...
    "id": "d71oyfk",
    // ...
    "body": "I just want to see what stacks people are using out there."
    // ...
  },
  "d720vlw": {
    // ...
    "replies": "",
    // ...
    "id": "d720vlw",
    // ...
    "body": "This. The database should be so far removed that it doesn't affect React one iota. I would even go so far as to say this post is off topic. "
    // ...
  },
  "d71nyho": {
    // ...
    "replies": [
      "d71oyfk",
      "d720vlw"
    ],
    // ...
    "id": "d71nyho",
    // ...
    "body": "Why does it matter? React should be a few layers removed from any database and it's quite agnostic about the backend. Heck, React itself doesn't even know how to talk to the backend. "
    // ...
  }
}