Added in Select2 4.0.0. This method was added to make upgrading easier from earlier versions of Select2.
    During the Select2 4.0.0 release, the
    matcher function was changed to allow for more complex
    matching of nested objects.
  
matcher
        term and the data object
          text.
        oldMatcher
        
    The custom matcher example provides a
    guide for how to use this in your own application. For those upgrading
    from older versions of Select2, you just need to wrap your old
    matcher with this function to maintain compatibility.