title: TypeError: Cannot read property 'title' of undefined
body: <p>Javascript - Node.js - Express - MongoDB - mongoose</p>
  
  <p>I have a forEach() method that runs a for loop on each user adding/removing items in an array. It successfully adds the appropriate amount of items for one user, but fails to add the rest of the items. How is taskList.title 'undefined' with items remaining inside the Array? </p>
  
  <pre><code>User.find({}, function(err, allUsers){
      if(err){
          console.log(err);
      } else {
          console.log("Total Users: ", Number(allUsers.length));
          console.log("Users are: ", allUsers);
          Task.find({}, function(err, taskList){
              if(err){
                  console.log(err);
              } else {
                  console.log("Your task list: " , taskList);
                  console.log("First item: " , taskList[0].title);
  
                  let n = (Math.floor(Number(taskList.length) / Number(allUsers.length)));
                  console.log("Users have", n , "items.");
                  console.log("===============================");
                  //assign n items to each user
  
                 //line 151 
                  allUsers.forEach(function addItem(user){
                      for(var i = 0; i &lt; n; i++){
                          user.items.push(taskList[i].title);
                          taskList.splice(i,1);
                          console.log('item added!');
                          console.log(user.name+":", user.items);
                          console.log(taskList.length , "items remain.";
                      }
                  });
  
              }
          });
      }
  });
  
  
  events.js:160
        throw er; // Unhandled 'error' event
        ^
  TypeError: Cannot read property 'title' of undefined
      at addItem (/home/ubuntu/workspace/v1.4/app.js:151:56)
      at Array.forEach (native)
      at /home/ubuntu/workspace/v1.4/app.js:149:30
      at /home/ubuntu/workspace/v1.4/node_modules/mongoose/lib/model.js:4485:16
      at process.nextTick (/home/ubuntu/workspace/v1.4/node_modules/mongoose/lib/helpers/query/completeMany.js:35:39)
      at _combinedTickCallback (internal/process/next_tick.js:73:7)
      at process._tickCallback (internal/process/next_tick.js:104:9)
  </code></pre>