判断一个字符串中出现次数最多的字符

let a = "aaaaaaaaadsdfdfdfeeeeeeee";
let json = {}
for(let i=0;i<a.length;i++){
	if(!json[a[i]]){
		json[a[i]] =1
	}else{
		json[a[i]]++
	}
}
console.log(json)
let maxNum = 0
let maxStr;
for(let i in json){
	if(json[i]>maxNum){
		maxNum = json[i]
		maxStr = i
	}
}
console.log("出现次数最多的字符是"+maxStr+",出现了"+maxNum+"次")