How to filter out a key from a second level object of a nested array of objects

Question

I am trying to filter out a key, in this case, count from a nested array of objects.

I have

let test  = [
 {
  "id": "c3c6f410f58e5836431b473ebcf134756232d04f2bf35edff8",
  "label": "Sector2",
  "options": {
   "62f92fab79ac81d933765bd0bbc4a1f5ea26cb3a088bcb4e6e": {
    "index": 0,
    "value": "Bob",
    "label": "Bob",
    "count": 1
   },
   "2fe91aa3567c0d04c521dcd2fc7e40d7622bb8c3f594d503da": {
    "index": 1,
    "value": "Student",
    "label": "Student",
    "count": 1
   },
   "c59ea1159f33b91a7f6edc6925be5e373fc543e4": {
    "index": 2,
    "value": "BBB",
    "label": "BBB",
    "count": 1
   },
   "c59ea1159f33b91a7f6edc6925be5e373fc54AAA": {
    "index": 3,
    "value": "Orange Duck",
    "label": "Orange Duck",
    "count": 1
   }
  }
 },
 {
  "id": "f794c6a52e793ee6f5c42cd5df6b4435236e3495e951709485",
  "label": "Brown Cow"
 },
 {
  "id": "f794c6a52e793ee6f5c42cd5df6b4435236e3495e95170ZZZ",
  "label": "Red Fish"
 }
]

 test = test.filter(item => item[0].options['count']);

but I am getting Cannot read properties of undefined

I am trying to filter out count from all elements of test that have options

desired output is

Thanks

[
 {
  "id": "c3c6f410f58e5836431b473ebcf134756232d04f2bf35edff8",
  "label": "Sector2",
  "options": {
   "62f92fab79ac81d933765bd0bbc4a1f5ea26cb3a088bcb4e6e": {
    "index": 0,
    "value": "Bob",
    "label": "Bob"
   },
   "2fe91aa3567c0d04c521dcd2fc7e40d7622bb8c3f594d503da": {
    "index": 1,
    "value": "Student",
    "label": "Student"
   },
   "c59ea1159f33b91a7f6edc6925be5e373fc543e4": {
    "index": 2,
    "value": "BBB",
    "label": "BBB",
    "count": 1
   },
   "c59ea1159f33b91a7f6edc6925be5e373fc54AAA": {
    "index": 3,
    "value": "Orange Duck",
    "label": "Orange Duck"
   }
  }
 },
 {
  "id": "f794c6a52e793ee6f5c42cd5df6b4435236e3495e951709485",
  "label": "Brown Cow"
 },
 {
  "id": "f794c6a52e793ee6f5c42cd5df6b4435236e3495e95170ZZZ",
  "label": "Red Fish"
 }
]

Answer 1

filter() is used to filter a portion of an array, not to delete nested keys of an object.

---

The easiest way to achieve your desired result it to:

1. Loop over each object
2. If this object has options
3. Loop over each options
4. Use delete to delete the count of the current object

const data = [{"id": "c3c6f410f58e5836431b473ebcf134756232d04f2bf35edff8", "label": "Sector2", "options": {"62f92fab79ac81d933765bd0bbc4a1f5ea26cb3a088bcb4e6e": {"index": 0, "value": "Bob", "label": "Bob", "count": 1 }, "2fe91aa3567c0d04c521dcd2fc7e40d7622bb8c3f594d503da": {"index": 1, "value": "Student", "label": "Student", "count": 1 }, "c59ea1159f33b91a7f6edc6925be5e373fc543e4": {"index": 2, "value": "BBB", "label": "BBB", "count": 1 }, "c59ea1159f33b91a7f6edc6925be5e373fc54AAA": {"index": 3, "value": "Orange Duck", "label": "Orange Duck", "count": 1 } } }, {"id": "f794c6a52e793ee6f5c42cd5df6b4435236e3495e951709485", "label": "Brown Cow" }, {"id": "f794c6a52e793ee6f5c42cd5df6b4435236e3495e95170ZZZ", "label": "Red Fish" } ];

for (let i in data) {
    if (data[i]?.options) {
        for (let j in data[i].options) {
            delete data[i].options[j]?.count;
        }
    }
}

console.log(data);