Determine whether a property of each object in an array of objects is the same

let arr = [
    {
        name: '小明',
        age: 18
    },
    {
        name: '小花',
        age: 18
    }
]

//判断某个属性是否重复

function isRepeat(arr,key) {
    let set = new Set;     //根据Set的特性做判断
    arr.forEach(item=>{
        set.add(item[key])
    })
    return set.size === 1
}

//判断name和age属性是不是相同

console.log(isRepeat(arr,'name'));  //false
console.log(isRepeat(arr,'age'));   //true