Updating intersect helper to work with ManyArrays.

addon/helpers/intersect.js

@@ -1,5 +1,5 @@
 import { helper } from '@ember/component/helper';
-import { isArray as isEmberArray } from '@ember/array';
+import { isArray as isEmberArray, A as emberArray } from '@ember/array';
 
 export function intersect([...arrays]) {
   let confirmedArrays = arrays.map(array => {
@@ -9,9 +9,9 @@ export function intersect([...arrays]) {
   let results = confirmedArrays.pop().filter(candidate => {
     for (let i = 0; i < arrays.length; i++) {
       let found = false;
-      let array = arrays[i];
+      let array = emberArray(arrays[i]);
       for (let j = 0; j < array.length; j++) {
-        if (array[j] === candidate) {
+        if (array.objectAt(j) === candidate) {
           found = true;
           break;
         }

tests/integration/helpers/intersect-test.js

@@ -51,4 +51,29 @@ module('Integration | Helper | {{intersect}}', function(hooks) {
 
     assert.equal(find('*').textContent.trim(), 'this is all that will render', 'no error is thrown');
   });
+
+  test('it accepts an ember data array', async function(assert) {
+    let store = this.owner.lookup('service:store');
+    let person = store.createRecord('person', {
+      name: 'Adam'
+    });
+
+    person.get('pets').pushObjects([
+      store.createRecord('pet', { name: 'Kirby' }),
+      store.createRecord('pet', { name: 'Jake' })
+    ]);
+
+    store.createRecord('pet', { name: 'Eva' });
+
+    this.set('person', person);
+    this.set('allPets', store.peekAll('pet'));
+
+    await this.render(hbs`
+      {{~#each (intersect person.pets allPets) as |pet|~}}
+        {{~pet.name~}}
+      {{~/each~}}
+    `);
+
+    assert.equal(this.element.textContent.trim(), 'KirbyJake', 'the pets belonging to the person are shown');
+  });
 });