1. js对象的最大深度

function findDeep(obj){
	if(obj&&obj instanceof Object&&!(obj instanceof Array)){
		let max=null;
		let flag=false;
		for(let key in obj){
			let des=findDeep(obj[key])+1;
			if(!flag){
				flag=true;
				max=des;
			}else{
				max=max<des?des:max;
			}
		}
		return max;
	}else{
		return 0;
	}
};