Compare objects in two arrays and return based on match in javascript

Question

I am using React for this, but the concept is in javascript. So hopefully I can leave React code out for simplicity sake.

I have two arrays that I need to filter out. My

Answer 1

Your problem is you are comparing index-by-index. You want to know if the element in arr1 is anywhere in arr2, right?

I would use arr2.filter to search all of arr2. So you would have something like this:

return arr1.map((e1, i) => {
  if (arr2.filter(e2 => e2.id === e1.id).length > 0) {  // If there's a match
    return 
Match
  } else {
    return 
No Match
  }
})

UPDATE: As recommended in the comments using Array.some is better here:

return arr1.map((e1, i) => {
  if (arr2.some(e2 => e2.id === e1.id)) {  // If there's a match
    return 
Match
  } else {
    return 
No Match
  }
})