js判断对象是否为空

js判断对象是否为空

//判断变量是否为空
  function isNull(obj){
	  const a = getVariableType(obj);
	  console.log(a)
	  switch (a) {
		case "undefined":
			return true;
			
		case "string":
			obj = obj.trim();
			if (obj=='' || obj==null || obj =="undefined"){
				return true;
			}else{
				return false;
			}
		case "boolean":
			return false;
		case "number":
			return false;
		case "array":
			if(obj.length==0){
				return true;
			}else{
				return false;
			}
		case "json":
			var str = JSON.stringify(obj);
			if(str=="{}"){
				return true;
			}else{
				return false;
			}
		case "function":
			return false;
		case "date":
				return false;
		default:
			return true;
	  }
  }

  function isNotNull(i){
	return !isNull(i);
  }

  //获取变量的类型
  function getVariableType(obj){
	  if(obj==null){
		return "undefined";
	  }else{
		var type =  typeof(obj);
		if(type=="object"){
			if(obj.constructor==Array){//数组
				return "array"
			}else if(isDate(obj)){
				return "date";
			}else if(isJSON (obj)){
				return "json"
			}else{
				return "undefined";
			}
		}else{
			return type;
		}
	  }
  }

  //判断对象是否是时间
  function isDate(obj){
	return obj instanceof Date;
  }

  //判断对象是否是json
 function isJSON (obj) {
    if (typeof obj == 'string') {
        try {
            var obj2 = JSON.parse(obj);
            if (typeof obj2 == 'object' && obj2) {
                return true;
            } else {
                return false;
            }

        } catch (e) {
            console.log('error：' + str + '!!!' + e);
            return false;
        }
    } else if(typeof obj == 'object'){
		if(obj.constructor==Array){
			return false;
		}else{
			try {
				var str = JSON.stringify(obj);
				return true;
			}catch (e) {
				console.log('error：' + str + '!!!' + e);
				return false;
			}
		}
		

	}
}