Home How can i improve this Javascript code that arrange the array in ordered list first and put them in an array of array with same value?

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How can i improve this Javascript code that arrange the array in ordered list first and put them in an array of array with same value?

byMR

February 15, 2022

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);

>Solution :

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);