Javascript nested filters in Array of arrays

You could use a hash table for the selectedID and use it for fast filtering.

var full_list = [{ "pid": 1, "items": [{ "item_id": '9' }, { "item_id": '10' }, { "item_id": '12' }] }, { "pid": 2, "items": [{ "item_id": '33' }, { "item_id": '22' }, { "item_id": '65' }] }],
    tmp_list,
    selectedIDs = ['1', '9', '45'],
    selected = Object.create(null);

selectedIDs.forEach(function (a) {
    selected[a] = true;
});

tmp_list = full_list.filter(function (a) {
    return !a.items.some(function (b) {
        return selected[b.item_id];
    });
});

console.log(tmp_list);

ES6

var full_list = [{ "pid": 1, "items": [{ "item_id": '9' }, { "item_id": '10' }, { "item_id": '12' }] }, { "pid": 2, "items": [{ "item_id": '33' }, { "item_id": '22' }, { "item_id": '65' }] }],
    tmp_list,
    selectedIDs = ['1', '9', '45'],
    selected = Object.create(null);

selectedIDs.forEach(a => selected[a] = true);
tmp_list = full_list.filter(a => !a.items.some(b=> selected[b.item_id]));

console.log(tmp_list);


First of all, this line in your question is wrong

var selectedIDs = {'1', '9', '45', ....};

You cannot declare arrays using {}. Instead use []

For your problem you can use a pure functional approach using Array#filter and Array#some methods to get your desired result as below:

var full_list = [
  {
    "pid": 1,
    "items":[
      {"item_id": '9'},
      {"item_id": '10'},
      {"item_id": '12'}
    ]
  },
  {
    "pid": 2,
    "items":[
      {"item_id": '33'},
      {"item_id": '22'},
      {"item_id": '67'}
    ]
  },
  {
    "pid": 9,
    "items":[
      {"item_id": '33'},
      {"item_id": '22'},
      {"item_id": '65'}
    ]
  },
  {
    "pid": 7,
    "items":[
      {"item_id": '7'},
      {"item_id": '22'},
      {"item_id": '65'}
    ]
  }
];

var tmp_list = [
  {
    "pid": 2,
    "items":[
      {"item_id": '7'},
      {"item_id": '22'},
      {"item_id": '65'}
    ]
  }
];


function filterResult (selectedItems) {
  return full_list.filter(function (process) {
    return process.items.some(function(item){
      return selectedItems.indexOf(item.item_id) > -1;
    });
  });
}

var selectedItems = ['9', '7', '22', '10'];

tmp_list = tmp_list.concat(filterResult(selectedItems))

console.log(tmp_list);


function flattenResults(list, selections) {
  return list.reduce(function (accumulator, current) {
    var res = current.items.filter(function(item){
      return (selections.indexOf(item.item_id) > -1 
              && checkIfAlreadyExist());
              
      function checkIfAlreadyExist () {
        return accumulator.every(function (k) {
          return k.item_id !== item.item_id;
        });
      }        
    });   

    return accumulator.concat(res);
  }, []);
}

console.log(flattenResults(full_list, selectedItems));


You may do like this;

var full_list = [
        {
            "pid": 1,
            "items":[
                {"item_id": '9'},
                {"item_id": '10'},
                {"item_id": '12'}
            ]
        },
        {
            "pid": 2,
            "items":[
                {"item_id": '33'},
                {"item_id": '22'},
                {"item_id": '65'}
            ]
        }
],
  selectedIDs = ['1', '9', '45'],
     tempList = [];
tempList.push(full_list.filter(f => f.items.some(o => selectedIDs.includes(o.item_id))));
console.log(tempList);

Tags:

Javascript

Arrays

Filter

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