fix(errors): Always throw a new Error() so stacktraces are usable

Author: christopherthielen

src/components/UIRouter.tsx

@@ -32,7 +32,7 @@ export interface UIRouterProps {
 }
 
 /** @hidden */
-export const InstanceOrPluginsMissingError = new Error(`Router instance or plugins missing.
+export const InstanceOrPluginsMissingError = `Router instance or plugins missing.
  You must either provide a location plugin via the plugins prop:
  
  <UIRouter plugins={[pushStateLocationPlugin]} states={[···]}>
@@ -47,12 +47,10 @@ export const InstanceOrPluginsMissingError = new Error(`Router instance or plugi
  <UIRouter router={router}>
    <UIView />
  </UIRouter>
- `);
+ `;
 
 /** @hidden */
-export const UIRouterInstanceUndefinedError = new Error(
-  `UIRouter instance is undefined. Did you forget to include the <UIRouter> as root component?`
-);
+export const UIRouterInstanceUndefinedError = `UIRouter instance is undefined. Did you forget to include the <UIRouter> as root component?`;
 
 /**
  * @internalapi
@@ -84,7 +82,7 @@ export function useInitializeUIRouter(
       if (configFn) configFn(uiRouter.current);
       (states || []).forEach(state => uiRouter.current.stateRegistry.register(state));
     } else {
-      throw InstanceOrPluginsMissingError;
+      throw new Error(InstanceOrPluginsMissingError);
     }
 
     uiRouter.current.start();

src/components/UISref.tsx

@@ -18,6 +18,9 @@ import { UISrefActiveContext } from './UISrefActive';
 /** @hidden */
 let classNames = _classNames;
 
+/** @hidden */
+export const IncorrectStateNameTypeError = `State name provided to UISref (as 'to') must be a string.`;
+
 export interface UISrefProps {
   children?: any;
   to: string;
@@ -48,7 +51,7 @@ export function useUISref(to: string, params: { [key: string]: any } = {}, optio
 
   const { stateService, stateRegistry } = router;
   if (!isString(to)) {
-    throw new Error(`State name provided to UISref (as 'to') must be a string.`);
+    throw new Error(IncorrectStateNameTypeError);
   }
 
   useEffect(() => parentUISrefActiveAddStateInfo(to, params), []);

src/components/UIView.tsx

@@ -97,10 +97,9 @@ export interface UIViewState {
   props?: any;
 }
 
-export const TransitionPropCollisionError = new Error(
+export const TransitionPropCollisionError =
   '`transition` cannot be used as resolve token. ' +
-    'Please rename your resolve to avoid conflicts with the router transition.'
-);
+  'Please rename your resolve to avoid conflicts with the router transition.';
 
 /** @internalapi */
 export const UIViewContext = createContext<UIViewAddress>(undefined);
@@ -174,7 +173,7 @@ class View extends Component<UIViewProps, UIViewState> {
   componentDidMount() {
     const router = this.props.router;
     if (typeof router === 'undefined') {
-      throw UIRouterInstanceUndefinedError;
+      throw new Error(UIRouterInstanceUndefinedError);
     }
 
     // Check the context for the parent UIView's fqn and State
@@ -234,7 +233,7 @@ class View extends Component<UIViewProps, UIViewState> {
 
       let stringTokens: string[] = resolveContext.getTokens().filter(x => typeof x === 'string');
       if (stringTokens.indexOf('transition') !== -1) {
-        throw TransitionPropCollisionError;
+        throw new Error(TransitionPropCollisionError);
       }
 
       trans = injector.get(Transition);

src/components/hooks/useUIRouter.ts

@@ -1,11 +1,11 @@
 import { useContext } from 'react';
-import { UIRouterContext } from '../UIRouter';
+import { UIRouterContext, UIRouterInstanceUndefinedError } from '../UIRouter';
 
 /** Returns the UIRouter object from React Context */
 export function useUIRouter() {
   const router = useContext(UIRouterContext);
   if (!router) {
-    throw new Error(`UIRouter instance is undefined. Did you forget to include the <UIRouter> as root component?`);
+    throw new Error(UIRouterInstanceUndefinedError);
   }
   return router;
 }

src/core.ts

@@ -22,11 +22,11 @@ import { ReactViewConfig, reactViewsBuilder } from './reactViews';
 let viewConfigFactory = (node: [PathNode], config: ReactViewDeclaration) => new ReactViewConfig(node, config);
 
 /** @hidden */
-export const StartMethodCalledMoreThanOnceError = new Error(`
+export const StartMethodCalledMoreThanOnceError = `
   The Router.start() method has been called more than once.
 
   The <UIRouter> component calls start() as final step of the initialization and you shouldn't need to call it manually.
-`);
+`;
 
 /**
  * The main UIRouter object
@@ -65,7 +65,7 @@ export class UIRouterReact extends UIRouter {
   start(): void {
     // Throw error if user calls `start` more than once
     if (this.started) {
-      throw StartMethodCalledMoreThanOnceError;
+      throw new Error(StartMethodCalledMoreThanOnceError);
     } else {
       this.urlMatcherFactory.$get();
       this.urlRouter.listen();