Using namespaced functions in jQuery.fn

Question

This seems like it should be obvious, but I can not figure out how to properly use namespaced (dotted) function names in jQuery.fn.

More precisely, using this in a function embedded in an object returns the object. Not the jQuery object it was attached to via .fn

A simple example that works, not using namespaced functions: (Working example of the below)

 $.fn.isBigText=function(nBytes) {
    let ttext=this.val();
    if (this.val().length > nBytes ) alert('Too big: '+ttext);
 }
 $.fn.isSmallText=function(nBytes) {
    let ttext=this.val();
    if (ttext.length < nBytes ) alert('Too small: '+ttext);
  }
  function checkSize(evt) {  // alert if too small or big. 
     let jqText=$('#myTextArea') ; // should use evt, but for this example I am being explicit
     jqText.isBigText(20);
     jqText.isSmallText(10);
  }
  ...
  <textarea cols="80" rows="1" id="myTextArea" onChange="checkSize(this)">fill this in </textarea>

And a namespaced example that does NOT work. Not defining a .val() function causes a "TypeError: this.val is not a function" error. So for illustrative purposes, I define a .val() within myFuncsDef that always returns "This is not the val() I was looking for!"

//  this version does not work
 var myFuncsDef={
   val: function() {return 'This is not the val() I was looking for! '},
   bigText:function(nBytes) {
       let ttext=this.val();
        if (this.val().length > nBytes ) alert('Too big: '+ttext);
     } ,
   smallText:function(nBytes) {
      let ttext=this.val();
      if (ttext.length < nBytes ) alert('Too small: '+ttext);
    }
  }
  $.fn.myFuncs=myFuncsDef ;

  function checkSizeNs(evt) {  // alert if too small or big  (namespaced version)
    let jqText=$('#myTextAreaNs') ; // should use evt, but for this example I am being explicit
    jqText.myFuncs.bigText(20);
    jqText.myFuncs.smallText(10);
  }
  ...
  <textarea cols="30" rows="1" id="myTextAreaNs" onChange="checkSizeNs(this)">Fill this </textarea>

Perhaps there is a way of saving the proper value of this (the jqText) before calling an internal function (bigText or smallText)?

Of course I could use something like myFuncs_bigText instead of myFuncs.bigText ...but that seems like a step backward.