平均年齢の取得

ageプロパティを持つオブジェクトの配列を取得し、平均年齢を返すgetAverageAge(users)関数を作成してください。

平均の計算式は(age1 + age2 + ... + ageN) / Nです。

例えば

          let john = { name: "John", age: 25 };
let pete = { name: "Pete", age: 30 };
let mary = { name: "Mary", age: 29 };

let arr = [ john, pete, mary ];

alert( getAverageAge(arr) ); // (25 + 30 + 29) / 3 = 28
        

function getAverageAge(users) {
  return users.reduce((prev, user) => prev + user.age, 0) / users.length;
}

let john = { name: "John", age: 25 };
let pete = { name: "Pete", age: 30 };
let mary = { name: "Mary", age: 29 };

let arr = [ john, pete, mary ];

alert( getAverageAge(arr) ); // 28