Javascript 余烬反射联想

我试图实现“跟随者/跟随者”关系

app/templates/users.hbs---------------------------

{{#each model as |user|}}
   ...
  <button {{action 'follow' user}}>Follow</button>
{{/each}}

 follow(user){
   //currentUser is the one clicking on 'follow' button 
   //and it works.I can successfully alert it's properties.
   currentUser.get('followings').pushObject(user);
 },

...
followings: DS.hasMany('user',{inverse: null}),
followers: DS.hasMany('user',{inverse: null}),

app/models/user.js-----------------------

{{#each model as |user|}}
   ...
  <button {{action 'follow' user}}>Follow</button>
{{/each}}

 follow(user){
   //currentUser is the one clicking on 'follow' button 
   //and it works.I can successfully alert it's properties.
   currentUser.get('followings').pushObject(user);
 },

...
followings: DS.hasMany('user',{inverse: null}),
followers: DS.hasMany('user',{inverse: null}),

现在，这个解决方案导致了下面的错误

Uncaught TypeError: Cannot read the property 'modelName' of undefined at assertPolymorphicType.notifyRecordRelationshipAdded

试试这个：

followings: DS.hasMany('user', { inverse: 'followers' },
followers: DS.hasMany('user', { inverse: 'followings' },

试试这个：

followings: DS.hasMany('user', { inverse: 'followers' },
followers: DS.hasMany('user', { inverse: 'followings' },