Delete unmatching objects in nested array

Question

I got problem to use the splice method in a generic way in a nested array. So what I want is to delete objects in "bigArray"s "nestedArray"s if "filterArray" dosen´t have a reference for the object.

I´ve made an example of what I want to do. If you guys got a solution on how I can improve it in native javascript or with Lodash feel free to give input. I'm really stuck.

Expected result should be:

  sort.unsortedArray = { "bigArray" : [
  {"id": 1, "text" : "This should be visible when done",
    "nestedArray": [
      { "id": 2, "nestedText": "Sort me out!" }
    ]
  },
  { "id": 2, "text" : "This should be visible when done",
    "nestedArray": [
    { "id": 2, "nestedText": "This one should  be visible in the coming array" }
    ]
  }]}

Here´s a codepen for it.

 var sort = this;
var init = function(){
  sort.outObjects();
};
sort.filterArray = { "filter" : [
  { "id": 3, "groupId": 1 }, 
  { "id": 2, "groupId": 2 }]};

sort.unsortedArray = { "bigArray" : [
  {"id": 1, "text" : "This should be visible when done",
    "nestedArray": [
      { "id": 1, "nestedText":"Sort this one out!" }, 
      { "id": 2, "nestedText": "Sort me out!" }, 
      { "id": 3, "nestedText": "This one should  be visible in the coming array"}]},

  { "id": 2, "text" : "This should be visible when done",
    "nestedArray": [
      { "id": 1, "nestedText": "Sort me out!" }, 
      { "id": 2, "nestedText": "This one should  be visible in the coming array" }, 
      {"id": 3, "nestedText": "Sort this one out!" }]}
]},

sort.outObjects = function (){

  //Check that we got the objects in same scope
  if(sort.filterArray && sort.unsortedArray){

    //Loop through "bigArray" object
    for( var i = 0; i< sort.unsortedArray.length; i++){

    console.log("sort.unsortedArray.length : ", sort.unsortedArray.length);

      //Loop through each "nestedArray":s objects
      for( var j = 0; j< sort.unsortedArray[i].nestedArray.length; j++){
      console.log("sort.unsortedArray[i].nestedArray.length : ", sort.unsortedArray[i].nestedArray.length);

        //Loop through filterArray object and compare each object in nested array, if they dont match, delete them.

       for( var k = 0; k< sort.filterArray.length; k++){
        console.log("sort.filterArray.length : ", sort.filterArray.length);

        if(sort.filterArray[k].id != sort.unsortedArray[i].nestedArray[j].id){

         //Delete unmatching object from unsortedArray
          sort.unsortedArray[i].nestedArray.splice(j,1);

         console.log("sort.unsortedArray after splice : ", sort.unsortedArray);
       }
      }
    }
  }
  }
  else{
    console.log("Missing connection to object",sort.filterArray, sort.unsortedArray);
  }
}

init();

what do mean with "if "filterArray" dosen´t have a reference for the object" ? "bigArray" doesn't have any object with groupId property — RomanPerekhrest
– RomanPerekhrest, Commented Jun 2, 2016 at 9:06
@RomanPerekhrest, exactly! Thats the problem I'm facing. its only a reference to the bigArray:s objects. — Michael R
– Michael R, Commented Jun 2, 2016 at 9:07
@RomanPerekhrest, good idea! I added the expected result. Thank you. :) — Michael R
– Michael R, Commented Jun 2, 2016 at 9:16

Nina Scholz · Accepted Answer · 2016-06-02 10:57:51Z

1

You could generate an object for faster access and test for the final filtering.

After generating it, you could iterate over the data, check if a change is necessary and apply filtering.

Edit: Proposal for more than one id to keep.

var filterArray = { "filter": [{ "id": 3, "groupId": 1 }, { "id": 2, "groupId": 2 }] },
    unsortedArray = { "bigArray": [{ "id": 1, "text": "This should be visible when done", "nestedArray": [{ "id": 1, "nestedText": "Sort this one out!" }, { "id": 2, "nestedText": "Sort me out!" }, { "id": 3, "nestedText": "This one should  be visible in the coming array" }] }, { "id": 2, "text": "This should be visible when done", "nestedArray": [{ "id": 1, "nestedText": "Sort me out!" }, { "id": 2, "nestedText": "This one should  be visible in the coming array" }, { "id": 3, "nestedText": "Sort this one out!" }] }] },
    filterObject = Object.create(null);

filterArray.filter.forEach(function (a) {
    filterObject[a.groupId] = filterObject[a.groupId] || Object.create(null);
    filterObject[a.groupId][a.id] = true;
});

unsortedArray.bigArray.forEach(function (a) {
    if (a.id in filterObject) {
        a.nestedArray = a.nestedArray.filter(function (b) {
            return filterObject[a.id][b.id];
        });
    }
});
console.log(filterObject);
console.log(unsortedArray);

edited Jun 2, 2016 at 10:57

answered Jun 2, 2016 at 9:17

Nina Scholz

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10 Comments

Michael R Over a year ago

Brb I´ll try! Good suggestion! :)

RomanPerekhrest Over a year ago

@NinaScholz, your result differs from OP's expected result. Consider that

Nina Scholz Over a year ago

or the ops result does not match with the given data?

RomanPerekhrest Over a year ago

compare attentively the first nestedArray between your result and the OP's result. Attentively ...

Michael R Over a year ago

@NinaScholz, Yes! It worked on the real solution too! Nina rocks!!! Thank you big time! :D

|

Redu · Accepted Answer · 2016-06-02 14:48:31Z

This would be my solution;

var fa = { "filter" : [{ "id": 3, "groupId": 1 },{ "id": 2, "groupId": 2 }]},
   usa = { "bigArray" : [{"id": 1, "text" : "This should be visible when done", "nestedArray": [{ "id": 1, "nestedText":"Sort this one out!" },{ "id": 2, "nestedText": "Sort me out!" },{ "id": 3, "nestedText": "This one should  be visible in the coming array"}]},{ "id": 2, "text" : "This should be visible when done","nestedArray": [{ "id": 1, "nestedText": "Sort me out!" },{ "id": 2, "nestedText": "This one should  be visible in the coming array" },{"id": 3, "nestedText": "Sort this one out!" }]}]},
    sa = fa.filter.reduce((p,c) => { var f = p.find(f => f.id == c.groupId);
                                     f && (f.nestedArray = f.nestedArray.reduce((n,o) => o.id == c.id ? n.concat(o) : n,[]));
    	                             return p }
                                   ,usa.bigArray);
console.log(sa);

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