2722-join-two-arrays-by-id.ts

// Title: Join Two Arrays by ID
// Description:
//     Given two arrays arr1 and arr2, return a new array joinedArray.
//     All the objects in each of the two inputs arrays will contain an id field that has an integer value.
//     joinedArray is an array formed by merging arr1 and arr2 based on their id key.
//     The length of joinedArray should be the length of unique values of id.
//     The returned array should be sorted in ascending order based on the id key.
//     If a given id exists in one array but not the other, the single object with that id should be included in the result array without modification.
//     If two objects share an id, their properties should be merged into a single object:
//         If a key only exists in one object, that single key-value pair should be included in the object.
//         If a key is included in both objects, the value in the object from arr2 should override the value from arr1.
// Link: https://leetcode.com/problems/join-two-arrays-by-id/

function join(arr1: any[], arr2: any[]): any[] {
  const joinedMap = new Map<number, any>();

  for (const obj of [...arr1, ...arr2]) {
    if (!joinedMap.has(obj.id)) joinedMap.set(obj.id, {});
    Object.assign(joinedMap.get(obj.id), obj);
  }

  return [...joinedMap.entries()]
    .sort(([aKey], [bKey]) => aKey - bKey)
    .map(([key, val]) => val);
}