How can I use a for loop to selectively exclude specific elements in JSON objects within an array?

Question

How can I use a for loop to selectively exclude specific elements in JSON objects within an array?

My goal is to execute the function checkIsObjectEmptyOrNot only when the fields "name", "age", and "class" do not contain null values. In case all these values are null (excluding id and book_id), the function should return false. The filtering process must exclude id and book_id as they always have values from the Laravel backend.

 checkIsObjectEmptyOrNot(object){

        for (var key in object) {
            if (key != 'id' && key != 'book_id' && key != null) {
                break;
                return true;
            }
        }
        return false;
    }

For example, I have a Json array like this:

[
    {
         "id": 1,
         "book_id": 2,
         "name": "myname",
         "age": 25,
         "class":null,
    },
    {
        "id": 2,
        "book_id": 2,
        "name": "myname2",
        "age": 25,
        "class": null,
    },
    {
        "id": 3,
        "book_id": 2,
        "name": "myname3",
        "age": 25,
        "class": 10,
    },
]

javascript arrays json vue.js

Answer 1

Answer №1

If you're looking to filter out items based on certain criteria, you can make use of Array.filter function as shown in the snippet below. It will only return items that meet the specified conditions.

const arr = [
 {
 "id":1,
 "book_id":2,
 "name":"myname",
 "age":25,
 "class":null,
 },
{
 "id":2,
 "book_id":2,
 "name":"myname2",
 "age":25,
 "class":null,
 },
{
 "id":3,
 "book_id":2,
 "name":"myname3",
 "age":25,
 "class":10,
 },
].filter((item)=>{
  return item.name && item.age && item.class
})

console.log(arr);

Alternatively, you can use a custom function like the one provided below to check if specific properties in an object are not null or undefined. This function returns true if all required properties are present and valid.

const arr = [{
    "id": 1,
    "book_id": 2,
    "name": "myname",
    "age": 25,
    "class": null,
  },
  {
    "id": 2,
    "book_id": 2,
    "name": "myname2",
    "age": 25,
    "class": null,
  },
  {
    "id": 3,
    "book_id": 2,
    "name": "myname3",
    "age": 25,
    "class": 10,
  },
]

function checkIsObjectEmptyOrNot(object) {
     for (var key in object) {
        if (key !== 'id' && key !== 'book_id' && object[key] !== null)
            return true;
    }
    return false;
}

console.log(checkIsObjectEmptyOrNot(arr[0]));
console.log(checkIsObjectEmptyOrNot(arr[1]));
console.log(checkIsObjectEmptyOrNot(arr[2]));

This function will evaluate to true only if all the specified properties (name, age, class) are not null, undefined, or false. Otherwise, it will return false.

Hope this explanation helps you in your coding endeavors :)

Answer 2

If you're looking to filter out items based on certain criteria, you can make use of Array.filter function as shown in the snippet below. It will only return items that meet the specified conditions.

const arr = [
 {
 "id":1,
 "book_id":2,
 "name":"myname",
 "age":25,
 "class":null,
 },
{
 "id":2,
 "book_id":2,
 "name":"myname2",
 "age":25,
 "class":null,
 },
{
 "id":3,
 "book_id":2,
 "name":"myname3",
 "age":25,
 "class":10,
 },
].filter((item)=>{
  return item.name && item.age && item.class
})

console.log(arr);

Alternatively, you can use a custom function like the one provided below to check if specific properties in an object are not null or undefined. This function returns true if all required properties are present and valid.

const arr = [{
    "id": 1,
    "book_id": 2,
    "name": "myname",
    "age": 25,
    "class": null,
  },
  {
    "id": 2,
    "book_id": 2,
    "name": "myname2",
    "age": 25,
    "class": null,
  },
  {
    "id": 3,
    "book_id": 2,
    "name": "myname3",
    "age": 25,
    "class": 10,
  },
]

function checkIsObjectEmptyOrNot(object) {
     for (var key in object) {
        if (key !== 'id' && key !== 'book_id' && object[key] !== null)
            return true;
    }
    return false;
}

console.log(checkIsObjectEmptyOrNot(arr[0]));
console.log(checkIsObjectEmptyOrNot(arr[1]));
console.log(checkIsObjectEmptyOrNot(arr[2]));

This function will evaluate to true only if all the specified properties (name, age, class) are not null, undefined, or false. Otherwise, it will return false.

Hope this explanation helps you in your coding endeavors :)

Answer 3

Answer №2

Consider utilizing the forEach method.

var dataList = [
    {
        "id": 1,
        "book_id": 2,
        "name": "myname",
        "age": 25,
        "class": null
    },
    {
        "id": 2,
        "book_id": 2,
        "name": "myname2",
        "age": 25,
        "class": null
    },
    {
        "id": 3,
        "book_id": 2,
        "name": "myname3",
        "age": 25,
        "class": 10
    }
];
var flag = 0;
dataList.forEach(function(item) {
    for (let [key, value] of Object.entries(item)) {
        if (item[key] !== _id || item[key] !== book_id) {
            if (item[key] !== null) {
                flag = 1;
            }
        }
    }
});

if (flag === 0) {
    checkIsObjectEmptyOrNot();
}

Answer 4

Consider utilizing the forEach method.

var dataList = [
    {
        "id": 1,
        "book_id": 2,
        "name": "myname",
        "age": 25,
        "class": null
    },
    {
        "id": 2,
        "book_id": 2,
        "name": "myname2",
        "age": 25,
        "class": null
    },
    {
        "id": 3,
        "book_id": 2,
        "name": "myname3",
        "age": 25,
        "class": 10
    }
];
var flag = 0;
dataList.forEach(function(item) {
    for (let [key, value] of Object.entries(item)) {
        if (item[key] !== _id || item[key] !== book_id) {
            if (item[key] !== null) {
                flag = 1;
            }
        }
    }
});

if (flag === 0) {
    checkIsObjectEmptyOrNot();
}

How can I use a for loop to selectively exclude specific elements in JSON objects within an array?

Answer №1

Answer №2

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