Question 49660 in Javascript Question posted in
A very good W3school tutorial can be found here.

filter objects which do not have property and delete from array of objects in javascript

I have a requirement where in I need to remove the objects which do not have certain property and delete it from an array of objects in javascript.Below is the input.

var array=[
    {
        "id": "1",
        "name": "john",
        "grade": "grade 1"
    },
    {
        "id": "4",
        "name": "sam",
        "grade": "grade 1",
        "DOB": null,
        "marks": 73,
        "result":"PASS"
    },
    {
        "id": "3",
        "name": "peter",
        "grade": "grade 1"
    },
    {
        "id": "5",
        "name": "robin",
        "grade": "grade 1",
        "marks": 63,
    },
    {
        "id": "2",
        "name": "james",
        "grade": "grade 1",
        "DOB": null,
        "result":"PASS"
    }   
    ]

requirement is to remove objects which do not have marks or dob or result field. I tried the following code and it throws error at delete step

 const filteredArray = array.filter( item => {
        if(!(('DOB' in item)||('marks' in item)||('result' in item))){
            console.log("ITEM DOESN'T HAVE FIELDS___DELETING IT")
            delete item
        }
    })

The expected output is as follows

[
    {
        "id": "4",
        "name": "sam",
        "grade": "grade 1",
        "DOB": null,
        "marks": 73,
        "result":"PASS"
    },
    {
        "id": "5",
        "name": "robin",
        "grade": "grade 1",
        "marks": 63,
    },
    {
        "id": "2",
        "name": "james",
        "grade": "grade 1",
        "DOB": null,
        "result":"PASS"
    }   
    ]

How do I achieve it?

Tags:

3

Answers


  1. 0

    The callback function must return a value whose truth value indicates whether the element should be included in the result. It doesn’t delete elements by itself.

    const array = [{
    "id": "1",
    "name": "john",
    "grade": "grade 1"
  },
  {
    "id": "4",
    "name": "sam",
    "grade": "grade 1",
    "DOB": null,
    "marks": 73,
    "result": "PASS"
  },
  {
    "id": "3",
    "name": "peter",
    "grade": "grade 1"
  },
  {
    "id": "5",
    "name": "robin",
    "grade": "grade 1",
    "marks": 63,
  },
  {
    "id": "2",
    "name": "james",
    "grade": "grade 1",
    "DOB": null,
    "result": "PASS"
  }
];

const filteredArray = array.filter( item => ('DOB' in item)||('marks' in item)||('result' in item));

console.log(filteredArray);
    Login or Signup to reply.
  2. 0

    Try the following:

    const filteredArray = array.filter( item => item.DOB !== undefined || item.marks !== undefined || item.result !== undefined)

console.log(filteredArray)
    Login or Signup to reply.
  3. 0

    Simplest version

    const res = array.filter(({marks,DOB,result}) => marks || DOB || result)

console.log(res)
    <script>
  var array = [{
      "id": "1",
      "name": "john",
      "grade": "grade 1"
    },
    {
      "id": "4",
      "name": "sam",
      "grade": "grade 1",
      "DOB": null,
      "marks": 73,
      "result": "PASS"
    },
    {
      "id": "3",
      "name": "peter",
      "grade": "grade 1"
    },
    {
      "id": "5",
      "name": "robin",
      "grade": "grade 1",
      "marks": 63,
    },
    {
      "id": "2",
      "name": "james",
      "grade": "grade 1",
      "DOB": null,
      "result": "PASS"
    }
  ]
</script>
    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search