How to get the ids of nested array once the condition is met?

Question

I've a nested array, once the condition is met, it should give all the parent ids e.g. I've a data array, in which I should match the

• getParentIds(data, 182, []);
  • result: [96, 182];
• getParentIds(data, 174, []);
  • result: [109 , 219, 76 ,174];

var data = [{
  "id": 96,
  "name": "test1",
  "items": [{
    "id": 181,
    "name": "Yes",
    "items": []
  }, {
    "id": 182,
    "name": "No",
    "items": []
  }]
}, {
  "id": 109,
  "name": "Test5",
  "items": [{
    "id": 219,
    "name": "opt2",
    "items": [{
      "id": 76,
      "name": "test3",
      "items": [{
        "id": 173,
        "name": "Yes",
        "items": []
      }, {
        "id": 174,
        "name": "No",
        "items": [{
          "id": 100,
          "name": "test2",
          "items": [{
            "id": 189,
            "name": "Yes",
            "items": []
          }]
        }]
      }]
    }]
  }, {
    "id": 224,
    "name": "opt3",
    "items": []
  }]
}];


function getParentIds(data, id, parentIds) {
  if (!parentIds) {
    parentIds = [];
  }
  data.map(function(item) {
    if (item.id === id) {
      parentIds.push(item.id);
      return parentIds;
    } else if (item.items.length === 0) {
      // do nothing
    } else {
      return getParentIds(item.items, id, parentIds);
    }
  });
}

console.log("Array list: " + getParentIds(data, 182, []));

Could you give me any suggestion on this?

Answer 1

This was a cool problem. It took me more than I expected to solve it, but here's a breadth-first search implementation:

var data = [{
  "id": 96,
  "name": "test1",
  "items": [{
    "id": 181,
    "name": "Yes",
    "items": []
  }, {
    "id": 182,
    "name": "No",
    "items": []
  }]
}, {
  "id": 109,
  "name": "Test5",
  "items": [{
    "id": 219,
    "name": "opt2",
    "items": [{
      "id": 76,
      "name": "test3",
      "items": [{
        "id": 173,
        "name": "Yes",
        "items": []
      }, {
        "id": 174,
        "name": "No",
        "items": [{
          "id": 100,
          "name": "test2",
          "items": [{
            "id": 189,
            "name": "Yes",
            "items": []
          }]
        }]
      }]
    }]
  }, {
    "id": 224,
    "name": "opt3",
    "items": []
  }]
}];


function parentsOf( arr, id, parents){
    if (parents.length)
        return parents;
    // I use for(;;) instead of map() because I need the return to exit the loop
    for (var i = 0; i < arr.length; i++){
        if ( arr[i].id == id){
             //push the current element at the front of the parents array
             parents.unshift( arr[i].id );
             return parents;
        };
        if ( arr[i].items ){
            parents = parentsOf(arr[i].items, id, parents);
            // if the parents array has any elements in it it means we found the child
            if (parents.length){
                parents.unshift(arr[i].id);
                return parents;
            }
        }
    }
    return parents;
}

console.log("Array list for 182: " + parentsOf(data, 182, []));
console.log("Array list for 174: " + parentsOf(data, 174, []));