feat(auto-init): return initialized components (#1333)

Author: blikblum

packages/mdc-auto-init/index.js

@@ -37,6 +37,7 @@ function _emit(evtType, evtData, shouldBubble = false) {
  * Auto-initializes all mdc components on a page.
  */
 export default function mdcAutoInit(root = document, warn = CONSOLE_WARN) {
+  const components = [];
   const nodes = root.querySelectorAll('[data-mdc-auto-init]');
   for (let i = 0, node; (node = nodes[i]); i++) {
     const ctorName = node.dataset.mdcAutoInit;
@@ -63,9 +64,11 @@ export default function mdcAutoInit(root = document, warn = CONSOLE_WARN) {
       enumerable: false,
       configurable: true,
     });
+    components.push(component);
   }
 
   _emit('MDCAutoInit:End', {});
+  return components;
 }
 
 mdcAutoInit.register = function(componentName, Ctor, warn = CONSOLE_WARN) {

test/unit/mdc-auto-init/mdc-auto-init.test.js

@@ -138,3 +138,11 @@ test('#dispatches a MDCAutoInit:End event when all components are initialized -
   assert.isOk(evt !== null);
   assert.equal(evt.type, type);
 });
+
+test('#returns the initialized components', () => {
+  const root = setupTest();
+  const components = mdcAutoInit(root);
+
+  assert.equal(components.length, 1);
+  assert.isOk(components[0] instanceof FakeComponent);
+});