js 統計字符串中字符出現的次數並排序

如題，先統計，在排序

var ary = "asasDFGHadDfFFhjkMNJGBHGDsdfghjfghjkdfghjkl";
var obj = {};
var i = 0;
var objArr = [];

ary1 = ary.toLocaleLowerCase(); //將字符串轉爲小寫
for(i = 0; i < ary1.length; i++)
{
    key = ary1[i];
    if(obj[key]){
        obj[key]++;//對象中有這個字母
    }else{
        obj[key] = 1;//對象中沒有這個字母,把字母加到對象中
    }
}
console.log(obj);

for(var key in obj){//遍歷這個對象
	let item = {label:key,value:obj[key]};
    objArr.push(item);
}
console.log(objArr);

function sortId(a,b){  
    return a.value-b.value;  
}
objArr.sort(sortId);
console.log(objArr);