I have two nested array of objects, how to compare two array of objects by
id
from arrobj1 and assignId
from arrobj2 using javascript
So, I would to know how to compare array of objects by id and assignId and return array of objects using javascript
Tried
const result = arrobj1.filter(arr1 => {
arrobj2.find(arr2 => arr2.assignId === arr1.id)
});
var arrobj1 =[
{id: 1, name: 'xxx', value:100},
{id: 2, name: 'yyy', value:200},
{id: 3, name: 'zzz', value:400}
]
var arrobj2 =[
{country: 'IN', name: 'lina', assignId:2},
{country: 'MY', name: 'john', assignId:3},
{country: 'SG', name: 'peter', assignId:6}
]
Expected Code:
[
{id: 2, name: 'yyy', value:200},
{id: 3, name: 'zzz', value:400}
]
CodePudding user response:
You have it almost correct, but you need to return in your filter, either by explicitly adding the return
keyword or by removing the braces to use the arrow function's implicit return:
const result = arrobj1.filter(arr1 =>
arrobj2.find(arr2 => arr2.assignId === arr1.id)
)
// or
const result = arrobj1.filter(arr1 => {
return arrobj2.find(arr2 => arr2.assignId === arr1.id)
})
CodePudding user response:
We can combine Array.filter()
and Array.some()
to make it more simple
let result = arrobj1.filter(a1 => arrobj2.some(a2 => a2.assignId === a1.id) )
console.log(result)
For your code,the reason is that you have missing return
when invoke find
var arrobj1 =[
{id: 1, name: 'xxx', value:100},
{id: 2, name: 'yyy', value:200},
{id: 3, name: 'zzz', value:400}
]
var arrobj2 =[
{country: 'IN', name: 'lina', assignId:2},
{country: 'MY', name: 'john', assignId:3},
{country: 'SG', name: 'peter', assignId:6}
]
let result = arrobj1.filter(a1 => arrobj2.some(a2 => a2.assignId === a1.id) )
console.log(result)
CodePudding user response:
You can generally go with the filter
and some
combination as @flyingfox mentioned in the answer, But if you'd have thousands of records then your time complexity would increase which you can solve by removing the nested some
loop.
So more performant code would look like the following for a bigger data set.
And yes, Either use return with braces or simply remove the braces for one-liner returns!
var arrobj1 = [
{ id: 1, name: 'xxx', value: 100 },
{ id: 2, name: 'yyy', value: 200 },
{ id: 3, name: 'zzz', value: 400 },
]
var arrobj2 = [
{ country: 'IN', name: 'lina', assignId: 2 },
{ country: 'MY', name: 'john', assignId: 3 },
{ country: 'SG', name: 'peter', assignId: 6 },
]
var obj = {}
for (const elem of arrobj2) {
obj[elem.assignId] = true
}
let result = arrobj1.filter((a1) => obj[a1.id])
console.log(result)