// 計算一組陣列中key值相同的數量
    let arr = [
        {
            name: 'Mokeke',
            age: 10,
        },
        {
            name: 'caixia',
            age: 10,
        },
        {
            name: 'caixia',
            age: 10,
        },
        {
            name: 'zijian',
            age: 11,
        },
    ]

一、
    
 
function accont(arr) {
        let obj = {}
        for (let i = 0; i < arr.length; i++) {
            if (obj[arr[i].age]) {
                obj[arr[i].age] += 1
            } else {
                obj[arr[i].age] = 1
            }
        }
        return obj
    }
二、
    function accont(arr) {
        let obj 
 
= {}
        for (let i = 0; i < arr.length; i++) {
            if (obj[arr[i].age]) {
                obj[arr[i].age] += 1
                continue
            }
            obj[arr[i].age] = 1

        }
        return obj
    }

    let result = accont(arr)
    console.log(result, 'result')
    
 
for(let i in result){
        console.log(`鍵值為${i}的數量為${result[i]}`)
    }