Is there a way to identify the items that have been removed and added in an array by comparing an old array to a new array

Question

Is there a way to identify the items that have been removed and added in an array by comparing an old array to a new array

Consider the following scenario:

oldArray = [
    { id: 1, position: 'DEV OM'},
    { id: 2, position: 'Senior Developer'},
]

newArray = [
    { id: 2, position: 'Senior Developer'},
    { id: 3, position: 'Junior Developer'},
]

How can we identify the items that were added and removed from these arrays?

addedItems = getAddedItems(oldArray, newArray)
removedItems = getRemovedItems(oldArray, newArray)


// AddedItems 
[
    { id: 3, position: 'Junior Developer'}
]

// RemovedItems 
[
    { id: 1, position: 'DEV OM'}
]

This process is being implemented in a typescript/angular2 application

arrays typescript

Answer 1

Answer №1

One solution is to create a function that identifies the variance between two arrays:

let oldArray = [
    { id: 1, position: 'Software Engineer'},
    { id: 2, position: 'Front End Developer'}
]

let newArray = [
    { id: 2, position: 'Front End Developer'},
    { id: 3, position: 'Back End Developer'}
]

function findDifference(arrA,arrB) {
  return arrA.filter(itemA => !arrB.some(itemB => itemB.id === itemA.id));
}

console.log(findDifference(oldArray,newArray))
console.log(findDifference(newArray,oldArray))

Answer 2

One solution is to create a function that identifies the variance between two arrays:

let oldArray = [
    { id: 1, position: 'Software Engineer'},
    { id: 2, position: 'Front End Developer'}
]

let newArray = [
    { id: 2, position: 'Front End Developer'},
    { id: 3, position: 'Back End Developer'}
]

function findDifference(arrA,arrB) {
  return arrA.filter(itemA => !arrB.some(itemB => itemB.id === itemA.id));
}

console.log(findDifference(oldArray,newArray))
console.log(findDifference(newArray,oldArray))

Is there a way to identify the items that have been removed and added in an array by comparing an old array to a new array

Answer №1

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