I have 2 array of objects like
const arrayOne = [{id: 1, name: 'one'}, {id: 2, name: 'two'}, {id: 3, name: 'three'}];
const arrayTwo = [{id: 2, name: 'two'}, {id: 3, name: 'three'}];
Here, I need to compare both these arrays and remove matching objects from arrayOne, which should finally give
this.arrayOne = [{id: 1, name: 'one'}];
I tried like below but it is removing all objects from the array
this.arrayOne = this.arrayOne.filter(o1 => this.arrayTwo.some(o2 => o1.id === o2.id));
What I am doing wrong here? Please suggest. Thanks
const arrayOne = [
{ id: 1, name: "one" },
{ id: 2, name: "two" },
{ id: 3, name: "three" },
];
const arrayTwo = [
{ id: 2, name: "two" },
{ id: 3, name: "three" },
];
const arrayTwoIds = new Set(arrayTwo.map((el) => el.id));
const arrayOneFiltered = arrayOne.filter((el) => !arrayTwoIds.has(el.id));
console.log(arrayOneFiltered);
// [ { id: 1, name: 'one' } ]
Depending on the size of the array, creating a set can improve performance, as you do not need to loop over arrayTwo arrayOne.length times but only once. After that, you can look up the existence of an id in arrayTwo in constant time.
Yet, as pointed out in another answer, this is not necessary if the arrays are small (like in your example). In this case, you could also use this one-liner:
arrayOne = arrayOne.filter((elOne) => !arrayTwo.some((elTwo) => elOne.id === elTwo.id));
Here, arrayOne would need to be mutable, i.e. defined with let.
You can find it by comparing it with id.
And arrayOne must be a let.
let arrayOne = [{id: 1, name: 'one'}, {id: 2, name: 'two'}, {id: 3, name: 'three'}];
const arrayTwo = [{id: 2, name: 'two'}, {id: 3, name: 'three'}];
arrayOne = arrayOne.filter(one => !arrayTwo.find(two => one.id == two.id));
console.log(arrayOne);
const arrayOne = [{
id: 1,
name: 'one'
}, {
id: 2,
name: 'two'
}, {
id: 3,
name: 'three'
}];
const arrayTwo = [{
id: 2,
name: 'two'
}, {
id: 3,
name: 'three'
}];
const arrayTwoId = arrayTwo.map(el => (el.id)); // extract id from arrayTwo
const result = arrayOne.filter(el => !arrayTwoId.includes(el.id));
console.log(result);
arrayTwo.arrayTwo.