Deleting data from a complex array structure based on multiple condition

Question

I'm receiving the json data in the below format

[
   {
      "key":4,
      "data":{
         "choice":[
            {
               "id":"1.1"
            },
            {
               "id":"1.2"
            }
         ],
         "questionId":"1"
      }
   },
   {
      "key":4,
      "data":{
         "choice":[
            {
               
               "id":"1.1.1.1"
            },
            {
               "id":"1.1.1.2"
            },
            {
               "id":"1.1.1.3",
            }
         ],
         "questionId":"1.1"
      }
   },
   {
      "key":4,
      "data":{
         "choice":[
            {

               "id":"1.1.1.3.1.1" 
            },
            {
               "id":"1.1.1.3.1.2"
            }
         ],
         "questionId":"1.1.1.3"
      }
   },
   {
      "key":4,
      "data":{
         "choice":[
            {
               "id":"1.1.1.3.1.1.1.1"
            },
            {
               "id":"1.1.1.3.1.1.1.2"
            }
         ],
         "questionId":"1.1.1.3.1.1"
      }
   },
   {
      "key":5,
      "data":{
         "choice":[
            {
               "id":"2.1"
            },
            { 
               "id":"2.2"
            }
         ],
         "questionId":"2"
      }
   },
   {
      "key":5,
      "data":{
         "choice":[
            
         ],
         "questionId":"2.2"
      },
      }
]

and I want to delete the record from this array based on multiple condition which is as followed

The "key" ,suppose i pass key as 4 the only the records which has key as 4 should be considered for deletion nothing from key as 5 should be deleted
the second is the id suppose the id(this is inside choice) I get is "1.1.1.2" then only the records after that should be deleted

so for eg I get key as 4 and id as "1.1.1.2" then the expected output should be as followed

[

  {
      "key":4,
      "data":{
         "choice":[
            {
               "id":"1.1"
            },
            {
               "id":"1.2"
            }
         ],
         "questionId":"1"
      }
   },
   {
      "key":4,
      "data":{
         "choice":[
            {
               
               "id":"1.1.1.1"
            },
            {
               "id":"1.1.1.2"
            },
            {
               "id":"1.1.1.3",
            }
         ],
         "questionId":"1.1"
      }
   },
   {
      "key":5,
      "data":{
         "choice":[
            {
               "id":"2.1"
            },
            { 
               "id":"2.2"
            }
         ],
         "questionId":"2"
      }
   },
   {
      "key":5,
      "data":{
         "choice":[
            
         ],
         "questionId":"2.2"
      },
      }
]

I tried using splice inside forEach but seems with splice there is an unusual behavior when used inside foreach anyother approach for the same

My code that i was trying

  this.followUpQues.forEach(function(val,index,object) { 
    if(val.data.choice.filter(y=>y.id === item.id).length >= 1) {
          keyNumber = val.key;
          valueIndex = index;
    }
 })

so after getting key and index i tried to delete the records after the index found and having key value that is identified,but using splice inside the foreach has weird behaviour

Do you have any possible way to change the receiving data structure within the backend ? — Dilshan, Sep 12 '20 at 06:46
Does this answer your question? [How do I remove an object from an array with JavaScript?](https://stackoverflow.com/questions/3396088/how-do-i-remove-an-object-from-an-array-with-javascript) — kewlashu, Sep 12 '20 at 06:57

score 1 · Accepted Answer · answered Sep 12 '20 at 07:08

You can do this using simple for loop:

choiceFound = 0
for(let i = 0; i < questions.length; i++ ){
    let question = questions[i];
    if(question.key == 4){
        if(!choiceFound) {
            choiceFound = question.data.choice.find(c => c.id == "1.1.1.2") ? 1: 0;
        }
        else {
            questions.splice(i, 1); 
            i--;
        }
    }
}

Weilory · Answer 2 · 2020-09-12T07:38:30.580

let json = [
   {
      "key":4,
      "data":{
         "choice":[
            {
               "id":"1.1"
            },
            {
               "id":"1.2"
            }
         ],
         "questionId":"1"
      }
   },
   {
      "key":4,
      "data":{
         "choice":[
            {
               
               "id":"1.1.1.1"
            },
            {
               "id":"1.1.1.2"
            },
            {
               "id":"1.1.1.3",
            }
         ],
         "questionId":"1.1"
      }
   },
   {
      "key":4,
      "data":{
         "choice":[
            {

               "id":"1.1.1.3.1.1" 
            },
            {
               "id":"1.1.1.3.1.2"
            }
         ],
         "questionId":"1.1.1.3"
      }
   },
   {
      "key":4,
      "data":{
         "choice":[
            {
               "id":"1.1.1.3.1.1.1.1"
            },
            {
               "id":"1.1.1.3.1.1.1.2"
            }
         ],
         "questionId":"1.1.1.3.1.1"
      }
   },
   {
      "key":5,
      "data":{
         "choice":[
            {
               "id":"2.1"
            },
            { 
               "id":"2.2"
            }
         ],
         "questionId":"2"
      }
   },
   {
      "key":5,
      "data":{
         "choice":[
            
         ],
         "questionId":"2.2"
      },
      }
];

let inspect = (json, key, id) => json.map((it, i) => it.key !== key || i === 0 ? it : json[i-1].data.choice.map((k, v)=>k.id).includes(id) ? null : it).filter(it => it !== null);

console.log(inspect(json, 4, '1.1.1.2'));

Update

If you mean deleting everything after "1.1.1.2" appears, then

let inspect = (json, key, id) => {
   let processed = json.map((it, i) => it.key !== key || i === 0 ? it : json[i-1].data.choice.map((k, v)=>k.id).includes(id) ? null : it);
   return processed.filter((it, i)=>
       it == null ? false : it.key !== key || i < processed.indexOf(null)
   );
};

let res = inspect(json, 4, '1.1.1.2');
console.log(res);

score 0 · Answer 3 · answered Sep 12 '20 at 07:26

This problem could be broken down into two steps. First finding the first index that matches your desired predicate, then filtering the result set after the index over a give key. If you want to be most efficient, you can combine these steps, but code readability will suffer.

const data = [
   {
      "key":4,
      "data":{
         "choice":[
            {
               "id":"1.1"
            },
            {
               "id":"1.2"
            }
         ],
         "questionId":"1"
      }
   },
   {
      "key":4,
      "data":{
         "choice":[
            {
               
               "id":"1.1.1.1"
            },
            {
               "id":"1.1.1.2"
            },
            {
               "id":"1.1.1.3",
            }
         ],
         "questionId":"1.1"
      }
   },
   {
      "key":4,
      "data":{
         "choice":[
            {

               "id":"1.1.1.3.1.1" 
            },
            {
               "id":"1.1.1.3.1.2"
            }
         ],
         "questionId":"1.1.1.3"
      }
   },
   {
      "key":4,
      "data":{
         "choice":[
            {
               "id":"1.1.1.3.1.1.1.1"
            },
            {
               "id":"1.1.1.3.1.1.1.2"
            }
         ],
         "questionId":"1.1.1.3.1.1"
      }
   },
   {
      "key":5,
      "data":{
         "choice":[
            {
               "id":"2.1"
            },
            { 
               "id":"2.2"
            }
         ],
         "questionId":"2"
      }
   },
   {
      "key":5,
      "data":{
         "choice":[
            
         ],
         "questionId":"2.2"
      },
      }
];

const remove = (data, key, id) => {
  let result = data;
 
  // find first index that matches our predicate.
  // first the key has to match, and then the id must be contained within our choices.
  const index = data.findIndex((n) => {
    return n.key === key && n.data.choice.findIndex((m) => m.id === id) !== -1;
  });
 
  // did we find something? If so start filtering!
  if (index !== -1) {
    result = data.filter((n, i) => {
      // is this element before our filter index? or maybe its not the right key?
      // if either are true, keep the element.
      return i <= index || n.key !== key;
    });
 }
 
 return result;
};

console.log(remove(data, 4, "1.1.1.2"));

score 0 · Answer 4 · answered Sep 12 '20 at 09:44

Avoid nested if conditions

    choiceFound = 0
    for(let i = 0; i < questions.length; i++ ){
        let question = questions[i];
        if(question.key == 4 && !choiceFound){
           choiceFound = question.data.choice.find(c => c.id == "1.1.1.2") ? 1: 0;
         }
         else {
                questions.splice(i, 1); 
                i--;
            }
        }

Deleting data from a complex array structure based on multiple condition

4 Answers4

Update