Can this code be Improved? It arrange our array into sorted list(sortedArray) first and, the finalArray takes the final result;Example finalArray = [[1,1,1,1][2,2,2]...]
let array = [1, 2, 4, 591, 392, 391, 2, 5, 10, 2, 1, 1, 1, 20, 20]
let sortedArray = []
let finalArray = []
sortedArray = array.sort((a, b) => {
if (a > b) return 1;
if (a < b) return -1;
return sortedArray.push(a - b);
});
finalArray = sortedArray.reduce((item, index) => {
if (typeof item.last === 'undefined' || item.last !== index) {
item.last = index;
item.sortedArray.push([]);
}
item.sortedArray[item.sortedArray.length - 1].push(index);
return item;
}, {
sortedArray: []
}).sortedArray;
console.log(finalArray);You could group first and then sort by the first item of each array.
If you have only positive 32 bit intger values, you could omit sorting, because the object is sorted like an array.
const
array = [1, 2, 4, 591, 392, 391, 2, 5, 10, 2, 1, 1, 1, 20, 20],
result = Object
.values(array.reduce((r, v) => {
(r[v] ??= []).push(v);
return r;
}, {}))
.sort(([a], [b]) => a - b);
console.log(result);.as-console-wrapper { max-height: 100% !important; top: 0; }Here is a shorter version than yours and more readable than Nina's
let array = [1, 2, 4, 591, 392, 391, 2, 5, 10, 2, 1, 1, 1, 20, 20]
const finalArray = array.slice(0) // copy the array
.reduce((acc,cur) => {
const idx = acc.findIndex(item => item[0] === cur);
if (idx !=-1) acc[idx].push(cur); // just push
else acc.push([cur]); // push as array
return acc
},[])
.sort(([a],[b]) => a-b); // sort on the first entry
console.log(finalArray);