计算对象数组指定属性值的平均值 ​

import { averageBy } from 'warbler-js';
const result = averageBy(arr, key);

const averageBy = (arr, key) => arr.reduce((pre, cur) => pre + cur[key], 0) / arr.length;

import { averageBy } from 'warbler-js';
const fruits = [
  { name: 'Grapes', quantity: 2 },
  { name: 'Bananas', quantity: 5 },
  { name: 'Apples', quantity: 10 },
  { name: 'Grapes', quantity: 4 },
  { name: 'Grapes', quantity: 6 },
];
const result = averageBy(fruits, 'quantity');
console.log(result); //=> 5.4