feat(view): A view without anything to render defaults to `<ui-view><…

…/ui-view>`

- If a view has no `template`, `templateUrl`, `templateProvider`, `component`, `componentProvider`
then the default is a passthrough `ui-view`
- This also applies to states without any of those properties; a default view is created with `ui-view` passthrough

Closes #3178

src/ng1/statebuilders/views.ts

@@ -25,6 +25,9 @@ const hasAnyKey = (keys, obj) =>
  * and applies the state-level configuration to a view named `$default`.
  */
 export function ng1ViewsBuilder(state: State) {
+  // Do not process root state
+  if (!state.parent) return {};
+
   let tplKeys = ['templateProvider', 'templateUrl', 'template', 'notify', 'async'],
       ctrlKeys = ['controller', 'controllerProvider', 'controllerAs', 'resolveAs'],
       compKeys = ['component', 'bindings', 'componentProvider'],
@@ -39,9 +42,7 @@ export function ng1ViewsBuilder(state: State) {
     name = name || "$default";
     // Account for views: { header: "headerComponent" }
     if (isString(config)) config = { component: <string> config };
-    if (!Object.keys(config).length) return;
 
-    // Configure this view for routing to an angular 1.5+ style .component (or any directive, really)
     if (hasAnyKey(compKeys, config) && hasAnyKey(nonCompKeys, config)) {
       throw new Error(`Cannot combine: ${compKeys.join("|")} with: ${nonCompKeys.join("|")} in stateview: '${name}@${state.name}'`);
     }
@@ -73,9 +74,6 @@ export class Ng1ViewConfig implements ViewConfig {
 
   load() {
     let $q = services.$q;
-    if (!this.hasTemplate())
-      throw new Error(`No template configuration specified for '${this.viewDecl.$uiViewName}@${this.viewDecl.$uiViewContextAnchor}'`);
-
     let context = new ResolveContext(this.path);
     let params = this.path.reduce((acc, node) => extend(acc, node.paramValues), {});
 

src/ng1/templateFactory.ts

@@ -23,13 +23,15 @@ export class TemplateFactory {
    * that string,or `null` if no template is configured.
    */
   fromConfig(config: Ng1ViewDeclaration, params: any, context: ResolveContext) {
+    const defaultTemplate = "<ui-view></ui-view>";
+
     return (
       isDefined(config.template) ? this.fromString(config.template, params) :
       isDefined(config.templateUrl) ? this.fromUrl(config.templateUrl, params) :
       isDefined(config.templateProvider) ? this.fromProvider(config.templateProvider, params, context) :
       isDefined(config.component) ? this.fromComponent(config.component, config.bindings) :
       isDefined(config.componentProvider) ? this.fromComponentProvider(config.componentProvider, params, context) :
-      null
+      defaultTemplate
     );
   };
 

test/viewDirectiveSpec.js

@@ -431,6 +431,16 @@ describe('uiView', function () {
     expect($onInit).toHaveBeenCalled();
   }));
 
+  it('should default the template to a <ui-view>', inject(function ($state, $q) {
+    $stateProvider.state('abstract', { abstract: true });
+    $stateProvider.state('abstract.foo', { template: 'hello' });
+    elem.append($compile('<div><ui-view></ui-view></div>')(scope));
+    $state.transitionTo('abstract.foo');
+    $q.flush();
+
+    expect(elem.text()).toBe('hello');
+  }));
+
   describe('play nicely with other directives', function() {
     // related to issue #857
     it('should work with ngIf', inject(function ($state, $q, $compile) {