title: ng-zorror-antd nzSortFn debugging custom sort function
body: <p>I am trying to assign a custom sort function to a table header, I would like to reference the name of an existing sort function in the component to use, but nzSortFn only accepts an anonymous arrow function, and I guess doesn't have the scope/namespacing to call your function from inside the anon function,  so I am copying my sort function into the anonymous function used by nzSortFn, but it looks like that custom function is not being used, as I can't debug inside the anonymous function either with either debugger or console.log(). Anybody have any idea how to debug a custom sort function?</p>