javascript - 获取父数组及其所有子数组

Question

假设我有这种数据...

data = [{
    "_id" : "1",
    "parentId" : "thisPostId",
    "topLevelId" : "1",
    "text" : "<p>comment</p>",
},
{
    "_id" : "2",
    "parentId" : "1",
    "topLevelId" : "1",
    "text" : "<p>reply to comment</p>",
},
{
    "_id" : "3",
    "parentId" : "2",
    "topLevelId" : "1",
    "text" : "<p>reply to reply to comment</p>",
},
{
    "_id" : "4",
    "parentId" : "3",
    "topLevelId" : "1",
    "text" : "<p>reply to reply to reply to comment</p>",
}]

我需要删除评论及其所有子项...

如果要删除的评论是 _id:1，那么我需要一个 ["1","2","3","4"] 数组 ,,, 然后我可以运行 Coll.remove({_id:{$in:["1","2","3","4"]}}, callback);

如果要删除的评论是 _id:2，那么我需要一个 ["2","3","4"] 的数组

如果要删除的评论是 _id:3，那么我需要一个 ["3","4"] 数组

如果要删除的注释是 _id:4，那么我需要一个 ["4"] 数组

我试过了(不知道)...

_.forEach(data, function(value, key){
    _.pluck(_.where(key, { "parentId" : "2" }), '_id');
});

不工作...

任何有关 javascript/lodash/underscore 的帮助将不胜感激，，，

谢谢你...

Answer 1

这是另一种解释，使用 native Array.prototype.reduce 方法仅将子元素添加到返回的数组。

edit, didn't read question properly, this will now return the current id and all children.

var data = [{
    "_id" : "1",
    "parentId" : "thisPostId",
    "topLevelId" : "1",
    "text" : "<p>comment</p>",
},
{
    "_id" : "2",
    "parentId" : "1",
    "topLevelId" : "1",
    "text" : "<p>reply to comment</p>",
},
{
    "_id" : "3",
    "parentId" : "2",
    "topLevelId" : "1",
    "text" : "<p>reply to reply to comment</p>",
},
{
    "_id" : "4",
    "parentId" : "3",
    "topLevelId" : "1",
    "text" : "<p>reply to reply to reply to comment</p>",
}];

function getChildIds( arr, id ){
  var parentFound = false;
  return arr.reduce(function( ret, item ){
    if( parentFound === false && item._id == id ){
      parentFound = true;
    } 
    
    if( parentFound ) {
      ret = ret.concat( item._id );
    }
    
    return ret;
  }, []);
}

console.log( getChildIds(data, '1') );
console.log( getChildIds(data, '2') );
console.log( getChildIds(data, '3') );
console.log( getChildIds(data, '4') );

<script src="http://codepen.io/synthet1c/pen/WrQapG.js"></script>

any order, not sure why it's necessary thought.

var data = [{
  "_id": "2",
  "parentId": "1",
  "topLevelId": "1",
  "text": "<p>reply to comment</p>",
}, {
  "_id": "1",
  "parentId": "thisPostId",
  "topLevelId": "1",
  "text": "<p>comment</p>",
}, {
  "_id": "4",
  "parentId": "3",
  "topLevelId": "1",
  "text": "<p>reply to reply to reply to comment</p>",
}, {
  "_id": "3",
  "parentId": "2",
  "topLevelId": "1",
  "text": "<p>reply to reply to comment</p>",
}];

function getChildIdsInAnyOrder(arr, id) {
  return arr.reduce(function(ret, item) {
    if ( parseInt(item._id) >= parseInt(id) ) {
      ret = ret.concat(item._id);
    }
    return ret;
  }, []);
}

console.log(getChildIdsInAnyOrder(data, '1'));
console.log(getChildIdsInAnyOrder(data, '2'));
console.log(getChildIdsInAnyOrder(data, '3'));
console.log(getChildIdsInAnyOrder(data, '4'));

<script src="http://codepen.io/synthet1c/pen/WrQapG.js"></script>