/**
* @param {number[]} arr1
* @param {number[]} arr2
* @return {number[]}
*/
var relativeSortArray = function(arr1, arr2) {
const map = new Map()
const N = arr2.length
for(let i = 0; i < arr2.length; i++) {
map.set(arr2[i], i)
}
return arr1.sort((a,b) => {
a = map.has(a) ? map.get(a) : N + a
b = map.has(b) ? map.get(b) : N + b
return a – b
})
};
