util-JS判断任意类型变量yes或no是否为空

//判断任意类型变量yes或no是否为空exportfunctionisNull(val){//null或undefinedif(val===null||val===未定义）返回真；if(typeofval==='string'&&val.trim()==="")返回真；如果（typeofval==='boolean'）返回false；if(typeofval==='number')return!val;if(valinstanceofError)返回val.message==='';switch(Object.prototype.toString.call(val)){//字符串或数组case'[objectString]':case'[objectArray]':return!val.length;//MaporSetorFilecase'[objectFile]':case'[objectMap]':case'[objectSet]':{return!val.size}//PlainObjectcase'[objectObject]':{返回!Object.keys(val).length;}}返回假；}