text: import { 
      FETCH_COURSES, TOGGLE_ENROLLED 
  } from '../actions/types';
  
  export default function(state = [], action) {
      switch(action.type) {
          case FETCH_COURSES:
              
              return [
                  ...state,
                  ...action.payload
              ]
  
          case TOGGLE_ENROLLED:
          console.log(action.payload);
          const newCourses = state.map( course => {
              if(course.id == action.payload) {
                  course.enrolled = !course.enrolled
              }
              return course
          })
          return [
              ...newCourses
          ]
          default: 
              return state;
      }
  }