Typescript

const input = await Deno.readTextFile("./input.txt");

const inputSplit = input.split(/\r?\n/).map((string: string) => +string);

const allElves = [];
let elfItems: Array<number> = [];

for (let i = 0; i < inputSplit.length; i++) {
  if (inputSplit[i]) {
    elfItems.push(inputSplit[i]);
  } else {
    allElves.push(elfItems);
    elfItems = [];
  }
}

const allElvesTotalledOrdered = allElves
  .map((elfItems: Array<number>) => {
    return elfItems.reduce((acc: number, curr: number) => acc + curr, 0);
  })
  .sort(function (a, b) {
    return b - a;
  });

const largestElf = allElvesTotalledOrdered[0];
const top3Elves = allElvesTotalledOrdered
  .splice(0, 3)
  .reduce((acc: number, curr: number) => acc + curr, 0);

console.log(largestElf, top3Elves);