feat(stateService): add transition option 'supercede' so transition c…

…an be ignored if one is pending

src/state/stateService.ts

@@ -338,6 +338,10 @@ export class StateService {
 
  if (!ref.valid()) return <TransitionPromise>silentRejection(ref.error());
 
+ if (options.supercede === false && getCurrent()) {
+ return <TransitionPromise>Rejection.ignored('Another transition is in progress and supercede has been set to false in TransitionOptions for the transition. So the transition was ignored in favour of the existing one in progress.').toPromise();
+ }
+
  /**
  * Special handling for Ignored, Aborted, and Redirected transitions
  *

src/transition/interface.ts

@@ -73,6 +73,18 @@ export interface TransitionOptions {
  * You can define your own Transition Options inside this property and use them, e.g., from a Transition Hook
  */
  custom?: any;
+ /**
+ * This option may be used to cancel the active transition (if one is active) in favour of the this one.
+ * This is the default behaviour or ui-router.
+ *
+ *
+ * - When `true`, the active transition will be canceled and new transition will begin.
+ * - when `false`, the transition will be canceled if a transition is already running. This can be useful in cases where
+ * you only want to navigate to a different state if you are not already navigating somewhere.
+ *
+ * @default `true`
+ */
+ supercede?: boolean;
  /** @internalapi */
  reloadState?: StateObject;
  /** @internalapi

src/transition/transitionService.ts

@@ -49,6 +49,7 @@ export let defaultTransOpts: TransitionOptions = {
  inherit: false,
  notify: true,
  reload: false,
+ supercede: true,
  custom: {},
  current: () => null,
  source: 'unknown',

test/stateServiceSpec.ts

@@ -637,6 +637,25 @@ describe('stateService', function() {
  done();
  });
 
+ describe('when supercede TransitionOption is false', () => {
+ it('ignores transition if another transition is running', async done => {
+ $state.defaultErrorHandler(() => null);
+ await initStateTo(A);
+
+ const activeTransition = $state.transitionTo(B, {});
+ const superseded = await $state.transitionTo(C, {}, { supercede: false }).catch(err => err);
+
+ const result: Rejection = await superseded;
+ expect(result.type).toEqual(RejectType.IGNORED);
+
+ await activeTransition;
+
+ expect($state.current).toBe(B);
+
+ done();
+ });
+ });
+
  it('aborts pending transitions (last call wins)', async done => {
  $state.defaultErrorHandler(() => null);
  await initStateTo(A);