clean code

app/adapters/application.js

@@ -1,4 +1,16 @@
 import DS from 'ember-data';
+import { get } from '@ember/object';
 
 export default DS.RESTAdapter.extend({
+  buildURL(modelName, id, snapshot) {
+    let url = this._super(...arguments);
+    let parentResource = get(snapshot, 'adapterOptions.parentResource')
+    if (parentResource) {
+      let { modelName: parentModelName } = parentResource.constructor;
+      let parentAdapter = this.store.adapterFor(parentModelName);
+      let parentUrl = parentAdapter.buildURL(parentModelName, parentResource.id);
+      return `${parentUrl}${url}`;
+    }
+    return url;
+  }
 });

app/models/comment.js

@@ -1,6 +1,5 @@
 import DS from 'ember-data';
 
 export default DS.Model.extend({
-  content: DS.attr('string'),
-  post: DS.belongsTo('post')
+  content: DS.attr('string')
 });

app/models/post.js

@@ -2,6 +2,5 @@ import DS from 'ember-data';
 
 export default DS.Model.extend({
   title: DS.attr('string'),
-  content: DS.attr('string'),
-  comments: DS.hasMany('comment')
+  content: DS.attr('string')
 });

app/routes/posts/detail/comments.js

@@ -3,7 +3,6 @@ import Route from '@ember/routing/route';
 export default Route.extend({
   model() {
     let post = this.modelFor('posts.detail');
-    // return this.store.findAll('comment', { adapterOptions: { parentResource: post } });
     return this.store.findSubAll(post, 'comment');
   }
 });

app/routes/posts/detail/comments/detail.js

@@ -3,7 +3,6 @@ import Route from '@ember/routing/route';
 export default Route.extend({
   model({ comment_id }) {
     let post = this.modelFor('posts.detail');
-    // return this.store.findRecord('comment', comment_id, { adapterOptions: { parentResource: post } });
     return this.store.findSubRecord(post, 'comment', comment_id);
   }
 });

app/services/store.js

@@ -1,17 +1,15 @@
-import DS from 'ember-data';
+import DS from "ember-data";
+import { set } from '@ember/object';
 
+const { Store } = DS;
 
-export default DS.Store.extend({
-  findSubRecord(parentResource, resourceName, resourceId, options) {
-    options = options || {};
-    options.adapterOptions = options.adapterOptions || {};
-    Object.assign(options.adapterOptions, { parentResource });
-    return this.findRecord(resourceName, resourceId, options);
+export default Store.extend({
+  findSubAll(parentResource, modelName, options = {}) {
+    set(options, 'parentResource', parentResource);
+    return this.findAll(modelName, options);
   },
-  findSubAll(parentResource, resourceName, options) {
-    options = options || {};
-    options.adapterOptions = options.adapterOptions || {};
-    Object.assign(options.adapterOptions, { parentResource });
-    return this.findAll(resourceName, options);
+  findSubRecord(parentResource, modelName, id, options = {}) {
+    set(options, 'parentResource', parentResource);
+    return this.findRecord(modelName, id, options);
   }
 });

mock/db.json

@@ -11,6 +11,11 @@
       "id": 1,
       "content": "some comment",
       "post_id": 1
+    },
+    {
+      "id": 2,
+      "content": "some comment#",
+      "post_id": 2
     }
   ]
 }