03. School Grades js fundamentals v1 with Map

function solve(args) {
  const students = new Map();

  const average = (a, b) => {
    let aSum = 0;
    for (let i = 0; i < a[1].length; i++) {
      aSum += a[1][i];
    }

    let bSum = 0;
    for (let i = 0; i < b[1].length; i++) {
      bSum += b[1][i];
    }

    const aAverage = aSum / a[1].length;
    const bAverage = bSum / b[1].length;

    return aAverage - bAverage;
  };

  args.forEach((element) => {
    const tokens = element.split(' ');
    const name = tokens[0];
    const grades = tokens.splice(1, tokens.length).map(Number);


    if (!students.has(name)) {
      students.set(name, []);
      students.set(name, students.get(name).concat(grades));
    } else {
      students.set(name, students.get(name).concat(grades));
    }
  });

  const sortByAverage = Array.from(students).sort((a, b) => average(a, b));

  sortByAverage.forEach((element) => {
    const [name, grades] = element;

    console.log(`${name}: ${grades.join(', ')}`);
  });
}