[FEATURE] Adds support for parenless data decorators

Adds support for `@attr`, `@belongsTo`, `@hasMany` without parens

.eslintrc.js

@@ -3,7 +3,10 @@ module.exports = {
   parser: 'babel-eslint',
   parserOptions: {
     ecmaVersion: 2017,
-    sourceType: 'module'
+    sourceType: 'module',
+    ecmaFeatures: {
+      legacyDecorators: true
+    }
   },
   plugins: [
     'ember'

config/ember-try.js

@@ -42,6 +42,15 @@ module.exports = function() {
             }
           }
         },
+        {
+          name: 'ember-lts-3.12',
+          npm: {
+            devDependencies: {
+              'ember-data': '~3.12.0',
+              'ember-source': '~3.12.0'
+            }
+          }
+        },
         {
           name: 'ember-release',
           npm: {

index.js

@@ -9,8 +9,9 @@ module.exports = {
 
     let checker = new VersionChecker(this.project);
     let emberVersion = checker.forEmber();
+    let emberDataVersion = checker.for('ember-data');
 
-    this.shouldPolyfill = emberVersion.lt('3.10.0-alpha.1');
+    this.shouldPolyfill = emberVersion.lt('3.10.0-alpha.0') || emberDataVersion.lt('3.10.0-alpha.0');
   },
 
   included() {

tests/unit/action-test.js

@@ -6,6 +6,7 @@ import { setupRenderingTest, skip } from 'ember-qunit';
 import { render, click, findAll } from '@ember/test-helpers';
 import hbs from 'htmlbars-inline-precompile';
 
+
 function registerComponent(
   test,
   name,

tests/unit/data-test.js

@@ -67,4 +67,44 @@ module('ember-data', function(hooks) {
 
     assert.equal(names, expectedNames, 'The correct records are in the array');
   });
+
+  test('@attr can be used without parens', async function(assert) {
+    let Post = class extends DS.Model {
+      @DS.attr name;
+    };
+
+    register(`model:post`, Post);
+    stubAdapter();
+
+    let store = getService('store');
+    let posts = await store.peekAll('post');
+    let names = posts
+      .toArray()
+      .map(post => get(post, 'name'))
+      .join();
+
+    assert.equal(names, expectedNames, 'The correct records are in the array');
+  });
+
+  if (gte('ember-data', '3.11.0')) {
+    test('@attr works with module imports without parens', async function(assert) {
+      let { default: Model, attr } = window.require('@ember-data/model');
+
+      let Post = class extends Model {
+        @attr name;
+      };
+
+      register(`model:post`, Post);
+      stubAdapter();
+
+      let store = getService('store');
+      let posts = await store.peekAll('post');
+      let names = posts
+        .toArray()
+        .map(post => get(post, 'name'))
+        .join();
+
+      assert.equal(names, expectedNames, 'The correct records are in the array');
+    });
+  }
 });