Top method for identifying discrepancies in 2 arrays of objects

Question

Top method for identifying discrepancies in 2 arrays of objects

I'm currently working with two arrays of objects and trying to find the most efficient way to compare them to identify any differences.

https://i.sstatic.net/fIPnA.png

I apologize for posting the image, but I felt it was necessary for better clarity.

Can anyone suggest a faster and more optimized method in JavaScript to compare these two arrays and highlight any missing elements?

I have considered using nested loops with an if statement, but I believe there might be a more efficient approach available.

Here is the specific data structure I aim to extract while comparing arr1 and arr2:

{
    "id": 4,
    "name": "Date and Time"
}

javascript arrays object

Answer 1

Answer №1

To identify missing elements between two arrays, you can merge the arrays and then filter through to check if each element exists in both. If it does not exist in both, then it is considered extra.

a1.concat(a2).filter(a => a1.findIndex(f => f.id === a.id) == -1 || a2.findIndex(f => f.id === a.id) == -1)

let array1 = [{"id": 1,"name": "Date and Time"},{"id": 2,"name": "Date and Time"},{"id": 3,"name": "Date and Time"},{"id": 4,"name": "Date and Time"}]

let array2 = [{"id": 1,"name": "Date and Time"},{"id": 2,"name": "Date and Time"},{"id": 3,"name": "Date and Time"}]

const findMissingElements = (a1, a2) => a1.concat(a2).filter(a => a1.findIndex(f => f.id === a.id) == -1 || a2.findIndex(f => f.id === a.id) == -1)

console.log(findMissingElements(array1, array2))

Answer 2

To identify missing elements between two arrays, you can merge the arrays and then filter through to check if each element exists in both. If it does not exist in both, then it is considered extra.

a1.concat(a2).filter(a => a1.findIndex(f => f.id === a.id) == -1 || a2.findIndex(f => f.id === a.id) == -1)

let array1 = [{"id": 1,"name": "Date and Time"},{"id": 2,"name": "Date and Time"},{"id": 3,"name": "Date and Time"},{"id": 4,"name": "Date and Time"}]

let array2 = [{"id": 1,"name": "Date and Time"},{"id": 2,"name": "Date and Time"},{"id": 3,"name": "Date and Time"}]

const findMissingElements = (a1, a2) => a1.concat(a2).filter(a => a1.findIndex(f => f.id === a.id) == -1 || a2.findIndex(f => f.id === a.id) == -1)

console.log(findMissingElements(array1, array2))

Answer 3

Answer №2

To fulfill this requirement, there are various approaches that can be taken. I have also conducted a performance evaluation based on the three solutions outlined below. You can run the test suite provided here and choose a solution that best suits your project.

The first method involves filtering the array using the Array.filter() method and then finding the ID in another array with the help of the Array.find() method.

const arr1 = [{
    id: 1,
    name: "Weather"
}, {
    id: 2,
    name: "Geo Location"
}, {
    id: 3,
    name: "Device"
}];

const arr2 = [{
    id: 1,
    name: "Weather"
}, {
    id: 2,
    name: "Geo Location"
}, {
    id: 3,
    name: "Device"
}, {
    id: 4,
    name: "Date and Time"
}];

const res = arr2.filter((obj) => !arr1.find(({ id }) => obj.id === id));

console.log(res);

The second method utilizes the Array.includes() method.

const arr1 = [{
    id: 1,
    name: "Weather"
}, {
    id: 2,
    name: "Geo Location"
}, {
    id: 3,
    name: "Device"
}];

const arr2 = [{
    id: 1,
    name: "Weather"
}, {
    id: 2,
    name: "Geo Location"
}, {
    id: 3,
    name: "Device"
}, {
    id: 4,
    name: "Date and Time"
}];

const IDArray = arr1.map(obj => obj.id);

const res = arr2.filter(obj => !IDArray.includes(obj.id));

console.log(res);

The third method combines the Array.some() method with the Array.filter() method.

const arr1 = [{
    id: 1,
    name: "Weather"
}, {
    id: 2,
    name: "Geo Location"
}, {
    id: 3,
    name: "Device"
}];

const arr2 = [{
    id: 1,
    name: "Weather"
}, {
    id: 2,
    name: "Geo Location"
}, {
    id: 3,
    name: "Device"
}, {
    id: 4,
    name: "Date and Time"
}];

const res = arr2.filter(({ id }) => !arr1.some(x => x.id == id))

console.log(res)

Answer 4

To fulfill this requirement, there are various approaches that can be taken. I have also conducted a performance evaluation based on the three solutions outlined below. You can run the test suite provided here and choose a solution that best suits your project.

The first method involves filtering the array using the Array.filter() method and then finding the ID in another array with the help of the Array.find() method.

const arr1 = [{
    id: 1,
    name: "Weather"
}, {
    id: 2,
    name: "Geo Location"
}, {
    id: 3,
    name: "Device"
}];

const arr2 = [{
    id: 1,
    name: "Weather"
}, {
    id: 2,
    name: "Geo Location"
}, {
    id: 3,
    name: "Device"
}, {
    id: 4,
    name: "Date and Time"
}];

const res = arr2.filter((obj) => !arr1.find(({ id }) => obj.id === id));

console.log(res);

The second method utilizes the Array.includes() method.

const arr1 = [{
    id: 1,
    name: "Weather"
}, {
    id: 2,
    name: "Geo Location"
}, {
    id: 3,
    name: "Device"
}];

const arr2 = [{
    id: 1,
    name: "Weather"
}, {
    id: 2,
    name: "Geo Location"
}, {
    id: 3,
    name: "Device"
}, {
    id: 4,
    name: "Date and Time"
}];

const IDArray = arr1.map(obj => obj.id);

const res = arr2.filter(obj => !IDArray.includes(obj.id));

console.log(res);

The third method combines the Array.some() method with the Array.filter() method.

const arr1 = [{
    id: 1,
    name: "Weather"
}, {
    id: 2,
    name: "Geo Location"
}, {
    id: 3,
    name: "Device"
}];

const arr2 = [{
    id: 1,
    name: "Weather"
}, {
    id: 2,
    name: "Geo Location"
}, {
    id: 3,
    name: "Device"
}, {
    id: 4,
    name: "Date and Time"
}];

const res = arr2.filter(({ id }) => !arr1.some(x => x.id == id))

console.log(res)

Top method for identifying discrepancies in 2 arrays of objects

Answer №1

Answer №2

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