/** * 2722. Join Two Arrays by ID * https://leetcode.com/problems/join-two-arrays-by-id/ * Difficulty: Medium * * 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. */ /** * @param {Array} arr1 * @param {Array} arr2 * @return {Array} */ var join = function(arr1, arr2) { const map = new Map(); [...arr1, ...arr2].forEach(obj => map.set(obj.id, { ...map.get(obj.id), ...obj })); return Array.from(map.values()).sort((a, b) => a.id - b.id); };