let array = [{
    name: "John",
    ranking: 5
}, {
    name: "Sam",
    ranking: 4
}, {
    name: "Timi",
    ranking: 1
}, {
    name: "Devon",
    ranking: 7
}, {
    name: "Ismaila",
    ranking: 10
}, ]

function arrangeByRank(data) {
    data.sort(function(a, b) {
        return a.ranking - b.ranking;
    });
    return data
}
console.log(arrangeByRank(array))

/* expected output: [ { name: 'Timi', ranking: 1 },
  { name: 'Sam', ranking: 4 },
  { name: 'John', ranking: 5 },
  { name: 'Devon', ranking: 7 },
  { name: 'Ismaila', ranking: 10 } ]
  */

function rankingAvr(data) {
    let sum = 0;
    data.map(person => {
        sum = person.ranking + sum
    })
    return sum/data.length
}
console.log(rankingAvr(array))
/* expected output:
5.4 */