lambda vs anonymous differences.

lambda vs anonymous differences.

so I am trying to to this line of code.
  1. $('li:contains("sad")').click(()=>$(this).hide())
and through testing variations on this line I have determined that for some reason when using lambda, ()=>{result}, the $(this) returns a window jquery object but in an anonymous function, function(){return result}, $(this) returns the li element I am looking for.  Why would these two notations run differently but serve almost the same function.
[included html and js files in txt format for testing.]