Modify objects in resutl array when combining two arrays into one

Question

I have two arrays of objects (Array1 and Array2) that I must combine in one array (result).

If an value is present in both arrays, it should be only once in the final array.

If a value is not present in any of the arrays, it needs to be added with the boolean set to true.

Here's the situation:

const Array1 = [
{value: "id1", name: "Element1", boolean: false}, 
{value: "id2", name: "Element2", boolean: false}, 
{value: "id3", name: "Element3", boolean: false}
]

const Array2 = [
{value: "id1", name: "Element1", boolean: false}, 
{value: "id2", name: "Element2", boolean: false}, 
{value: "id4", name: "Element4", boolean: false}
]

Expected output:

const result = [
{value: "id1", name: "Element1", boolean: false}, 
{value: "id2", name: "Element2", boolean: false}, 
{value: "id3", name: "Element3", boolean: true}, 
{value: "id4", name: "Element4", boolean: true}
]

@evolutionxbox the main issue I have is setting the boolean to true if an element is not present in one of the arrays — foreignChimichurri, Dec 08 '21 at 11:04

score 1 · Accepted Answer · answered Dec 08 '21 at 11:08

You can easily achieve the result using Map

const Array1 = [
  { value: "id1", name: "Element1", boolean: false },
  { value: "id2", name: "Element2", boolean: false },
  { value: "id3", name: "Element3", boolean: false },
];

const Array2 = [
  { value: "id1", name: "Element1", boolean: false },
  { value: "id2", name: "Element2", boolean: false },
  { value: "id4", name: "Element4", boolean: false },
];

const map = new Map(Array1.map((o) => [o.value, [o]]));
Array2.forEach((o) =>
  map.has(o.value) ? map.get(o.value).push(o) : map.set(o.value, [o])
);
const result = [...map.values()].map((arr) =>
  arr.length > 1 ? arr[0] : { ...arr[0], boolean: true }
);

console.log(result);

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Modify objects in resutl array when combining two arrays into one

1 Answers1