comlpeted_exercises_noun.js

window.app = window.app || {}; 

(function() {
  "use strict";
  
  function truncate(div) {
    var excess = div.children('ul').children('li').slice(5);
  }
  
  function verb(elements) {
    elements.each(function(){
      truncate(this);
    });
  }
  
  app.completedExercisesNoun = {
    verb: verb,
  }
});

main.js

$(document).ready(function() {
  app.completedExercisesNoun.verb($(".completed .exercises"));
});