diff --git a/src/common/common.ts b/src/common/common.ts
index 99a311ba..8c4128bc 100644
--- a/src/common/common.ts
+++ b/src/common/common.ts
@@ -6,10 +6,10 @@
  * @packageDocumentation
  * @preferred
  */
-import { isFunction, isString, isArray, isRegExp, isDate } from './predicates';
-import { all, any, prop, curry, not } from './hof';
-import { services } from './coreservices';
-import { StateObject } from '../state/stateObject';
+import { isFunction, isString, isArray, isRegExp, isDate } from './predicates.js';
+import { all, any, prop, curry, not } from './hof.js';
+import { services } from './coreservices.js';
+import { StateObject } from '../state/stateObject.js';
 
 declare const global;
 export const root: any =
diff --git a/src/common/coreservices.ts b/src/common/coreservices.ts
index afa8102e..6e754f18 100644
--- a/src/common/coreservices.ts
+++ b/src/common/coreservices.ts
@@ -4,9 +4,9 @@
  *
  * @packageDocumentation
  */
-import { IInjectable, Obj } from './common';
-import { Disposable } from '../interface';
-import { UrlConfig, UrlService } from '../url';
+import { IInjectable, Obj } from './common.js';
+import { Disposable } from '../interface.js';
+import { UrlConfig, UrlService } from '../url/index.js';
 
 const noImpl = (fnname: string) => () => {
   throw new Error(`No implementation for ${fnname}. The framework specific code did not implement this method.`);
diff --git a/src/common/hof.ts b/src/common/hof.ts
index fc52c7e9..fe3123bc 100644
--- a/src/common/hof.ts
+++ b/src/common/hof.ts
@@ -6,7 +6,7 @@
  * @packageDocumentation
  */
 
-import { Predicate } from './common';
+import { Predicate } from './common.js';
 /**
  * Returns a new function for [Partial Application](https://en.wikipedia.org/wiki/Partial_application) of the original function.
  *
diff --git a/src/common/index.ts b/src/common/index.ts
index 9f3c4e4f..d3117bf8 100644
--- a/src/common/index.ts
+++ b/src/common/index.ts
@@ -1,8 +1,8 @@
-export * from './common';
-export * from './coreservices';
-export * from './glob';
-export * from './hof';
-export * from './predicates';
-export * from './queue';
-export * from './strings';
-export * from './trace';
+export * from './common.js';
+export * from './coreservices.js';
+export * from './glob.js';
+export * from './hof.js';
+export * from './predicates.js';
+export * from './queue.js';
+export * from './strings.js';
+export * from './trace.js';
diff --git a/src/common/predicates.ts b/src/common/predicates.ts
index db25543a..ff3bf5ea 100644
--- a/src/common/predicates.ts
+++ b/src/common/predicates.ts
@@ -6,9 +6,9 @@
  *
  * @packageDocumentation
  */
-import { and, not, pipe, prop, or } from './hof';
-import { Predicate } from './common'; // has or is using
-import { StateObject } from '../state/stateObject';
+import { and, not, pipe, prop, or } from './hof.js';
+import { Predicate } from './common.js'; // has or is using
+import { StateObject } from '../state/stateObject.js';
 
 const toStr = Object.prototype.toString;
 const tis = (t: string) => (x: any) => typeof x === t;
diff --git a/src/common/queue.ts b/src/common/queue.ts
index e43b8815..7f521a44 100644
--- a/src/common/queue.ts
+++ b/src/common/queue.ts
@@ -1,4 +1,4 @@
-import { pushTo } from './common';
+import { pushTo } from './common.js';
 
 export class Queue<T> {
   private _evictListeners: ((item: T) => void)[] = [];
diff --git a/src/common/safeConsole.ts b/src/common/safeConsole.ts
index b16c710c..3f2ca8b7 100644
--- a/src/common/safeConsole.ts
+++ b/src/common/safeConsole.ts
@@ -3,7 +3,7 @@
  * @packageDocumentation
  */
 /* tslint:disable:no-console */
-import { noop } from './common';
+import { noop } from './common.js';
 
 const noopConsoleStub = { log: noop, error: noop, table: noop };
 
diff --git a/src/common/strings.ts b/src/common/strings.ts
index 7c8d42d7..6e69e3ec 100644
--- a/src/common/strings.ts
+++ b/src/common/strings.ts
@@ -6,10 +6,10 @@
  * @packageDocumentation
  */
 
-import { isArray, isFunction, isInjectable, isNull, isObject, isPromise, isString, isUndefined } from './predicates';
-import { Rejection } from '../transition/rejectFactory';
-import { identity, IInjectable, pushR, tail } from './common';
-import { pattern, val } from './hof';
+import { isArray, isFunction, isInjectable, isNull, isObject, isPromise, isString, isUndefined } from './predicates.js';
+import { Rejection } from '../transition/rejectFactory.js';
+import { identity, IInjectable, pushR, tail } from './common.js';
+import { pattern, val } from './hof.js';
 
 /**
  * Returns a string shortened to a maximum length
diff --git a/src/common/trace.ts b/src/common/trace.ts
index 61f20846..12006d77 100644
--- a/src/common/trace.ts
+++ b/src/common/trace.ts
@@ -32,19 +32,19 @@
  *
  * @packageDocumentation
  */
-import { parse } from '../common/hof';
-import { isNumber } from '../common/predicates';
-import { Transition } from '../transition/transition';
-import { ViewTuple } from '../view';
-import { ActiveUIView, ViewConfig, ViewContext } from '../view/interface';
-import { stringify, functionToString, maxLength, padString } from './strings';
-import { safeConsole } from './safeConsole';
-import { Resolvable } from '../resolve/resolvable';
-import { PathNode } from '../path/pathNode';
-import { PolicyWhen } from '../resolve/interface';
-import { TransitionHook } from '../transition/transitionHook';
-import { HookResult } from '../transition/interface';
-import { StateObject } from '../state/stateObject';
+import { parse } from '../common/hof.js';
+import { isNumber } from '../common/predicates.js';
+import { Transition } from '../transition/transition.js';
+import { ViewTuple } from '../view/index.js';
+import { ActiveUIView, ViewConfig, ViewContext } from '../view/interface.js';
+import { stringify, functionToString, maxLength, padString } from './strings.js';
+import { safeConsole } from './safeConsole.js';
+import { Resolvable } from '../resolve/resolvable.js';
+import { PathNode } from '../path/pathNode.js';
+import { PolicyWhen } from '../resolve/interface.js';
+import { TransitionHook } from '../transition/transitionHook.js';
+import { HookResult } from '../transition/interface.js';
+import { StateObject } from '../state/stateObject.js';
 
 function uiViewString(uiview: ActiveUIView) {
   if (!uiview) return 'ui-view (defunct)';
diff --git a/src/globals.ts b/src/globals.ts
index ae2f5ee2..707b2858 100644
--- a/src/globals.ts
+++ b/src/globals.ts
@@ -1,9 +1,9 @@
-import { StateParams } from './params/stateParams';
-import { StateDeclaration } from './state/interface';
-import { StateObject } from './state/stateObject';
-import { Transition } from './transition/transition';
-import { Queue } from './common/queue';
-import { Disposable } from './interface';
+import { StateParams } from './params/stateParams.js';
+import { StateDeclaration } from './state/interface.js';
+import { StateObject } from './state/stateObject.js';
+import { Transition } from './transition/transition.js';
+import { Queue } from './common/queue.js';
+import { Disposable } from './interface.js';
 
 /**
  * Global router state
diff --git a/src/hooks/coreResolvables.ts b/src/hooks/coreResolvables.ts
index dccf5f27..ef2230f2 100644
--- a/src/hooks/coreResolvables.ts
+++ b/src/hooks/coreResolvables.ts
@@ -1,9 +1,9 @@
-import { Transition } from '../transition/transition';
-import { UIRouter } from '../router';
-import { TransitionService } from '../transition/transitionService';
-import { Resolvable } from '../resolve';
-import { inArray, uniqR, unnestR, values } from '../common';
-import { PathNode } from '../path';
+import { Transition } from '../transition/transition.js';
+import { UIRouter } from '../router.js';
+import { TransitionService } from '../transition/transitionService.js';
+import { Resolvable } from '../resolve/index.js';
+import { inArray, uniqR, unnestR, values } from '../common/index.js';
+import { PathNode } from '../path/index.js';
 
 function addCoreResolvables(trans: Transition) {
   trans.addResolvable(Resolvable.fromData(UIRouter, trans.router), '');
diff --git a/src/hooks/ignoredTransition.ts b/src/hooks/ignoredTransition.ts
index 217a719f..c4bff3e0 100644
--- a/src/hooks/ignoredTransition.ts
+++ b/src/hooks/ignoredTransition.ts
@@ -1,7 +1,7 @@
-import { trace } from '../common/trace';
-import { Rejection } from '../transition/rejectFactory';
-import { TransitionService } from '../transition/transitionService';
-import { Transition } from '../transition/transition';
+import { trace } from '../common/trace.js';
+import { Rejection } from '../transition/rejectFactory.js';
+import { TransitionService } from '../transition/transitionService.js';
+import { Transition } from '../transition/transition.js';
 
 /**
  * A [[TransitionHookFn]] that skips a transition if it should be ignored
diff --git a/src/hooks/invalidTransition.ts b/src/hooks/invalidTransition.ts
index 199417ff..45e08200 100644
--- a/src/hooks/invalidTransition.ts
+++ b/src/hooks/invalidTransition.ts
@@ -1,5 +1,5 @@
-import { TransitionService } from '../transition/transitionService';
-import { Transition } from '../transition/transition';
+import { TransitionService } from '../transition/transitionService.js';
+import { Transition } from '../transition/transition.js';
 
 /**
  * A [[TransitionHookFn]] that rejects the Transition if it is invalid
diff --git a/src/hooks/lazyLoad.ts b/src/hooks/lazyLoad.ts
index 1d891110..b40329bd 100644
--- a/src/hooks/lazyLoad.ts
+++ b/src/hooks/lazyLoad.ts
@@ -1,9 +1,9 @@
-import { Transition } from '../transition/transition';
-import { TransitionService } from '../transition/transitionService';
-import { TransitionHookFn } from '../transition/interface';
-import { StateDeclaration, LazyLoadResult } from '../state/interface';
-import { services } from '../common/coreservices';
-import { StateRule } from '../url/interface';
+import { Transition } from '../transition/transition.js';
+import { TransitionService } from '../transition/transitionService.js';
+import { TransitionHookFn } from '../transition/interface.js';
+import { StateDeclaration, LazyLoadResult } from '../state/interface.js';
+import { services } from '../common/coreservices.js';
+import { StateRule } from '../url/interface.js';
 
 /**
  * A [[TransitionHookFn]] that performs lazy loading
diff --git a/src/hooks/onEnterExitRetain.ts b/src/hooks/onEnterExitRetain.ts
index 21a9e621..c59ff63c 100644
--- a/src/hooks/onEnterExitRetain.ts
+++ b/src/hooks/onEnterExitRetain.ts
@@ -1,8 +1,8 @@
-import { TransitionStateHookFn } from '../transition/interface';
-import { Transition } from '../transition/transition';
-import { TransitionService } from '../transition/transitionService';
-import { StateDeclaration } from '../state/interface';
-import { StateObject } from '../state/stateObject';
+import { TransitionStateHookFn } from '../transition/interface.js';
+import { Transition } from '../transition/transition.js';
+import { TransitionService } from '../transition/transitionService.js';
+import { StateDeclaration } from '../state/interface.js';
+import { StateObject } from '../state/stateObject.js';
 
 /**
  * A factory which creates an onEnter, onExit or onRetain transition hook function
diff --git a/src/hooks/redirectTo.ts b/src/hooks/redirectTo.ts
index e9cdaf6b..61648605 100644
--- a/src/hooks/redirectTo.ts
+++ b/src/hooks/redirectTo.ts
@@ -1,9 +1,9 @@
-import { isString, isFunction } from '../common/predicates';
-import { Transition } from '../transition/transition';
-import { services } from '../common/coreservices';
-import { TargetState } from '../state/targetState';
-import { TransitionService } from '../transition/transitionService';
-import { TransitionHookFn } from '../transition/interface';
+import { isString, isFunction } from '../common/predicates.js';
+import { Transition } from '../transition/transition.js';
+import { services } from '../common/coreservices.js';
+import { TargetState } from '../state/targetState.js';
+import { TransitionService } from '../transition/transitionService.js';
+import { TransitionHookFn } from '../transition/interface.js';
 
 /**
  * A [[TransitionHookFn]] that redirects to a different state or params
diff --git a/src/hooks/resolve.ts b/src/hooks/resolve.ts
index 8f9665ee..010e39c3 100644
--- a/src/hooks/resolve.ts
+++ b/src/hooks/resolve.ts
@@ -1,10 +1,10 @@
-import { noop } from '../common/common';
-import { Transition } from '../transition/transition';
-import { ResolveContext } from '../resolve/resolveContext';
-import { TransitionStateHookFn, TransitionHookFn } from '../transition/interface';
-import { TransitionService } from '../transition/transitionService';
-import { val } from '../common/hof';
-import { StateDeclaration } from '../state/interface';
+import { noop } from '../common/common.js';
+import { Transition } from '../transition/transition.js';
+import { ResolveContext } from '../resolve/resolveContext.js';
+import { TransitionStateHookFn, TransitionHookFn } from '../transition/interface.js';
+import { TransitionService } from '../transition/transitionService.js';
+import { val } from '../common/hof.js';
+import { StateDeclaration } from '../state/interface.js';
 
 export const RESOLVE_HOOK_PRIORITY = 1000;
 
diff --git a/src/hooks/updateGlobals.ts b/src/hooks/updateGlobals.ts
index 4e0517f3..2d156895 100644
--- a/src/hooks/updateGlobals.ts
+++ b/src/hooks/updateGlobals.ts
@@ -1,6 +1,6 @@
-import { Transition } from '../transition/transition';
-import { copy } from '../common/common';
-import { TransitionService } from '../transition/transitionService';
+import { Transition } from '../transition/transition.js';
+import { copy } from '../common/common.js';
+import { TransitionService } from '../transition/transitionService.js';
 
 /**
  * A [[TransitionHookFn]] which updates global UI-Router state
diff --git a/src/hooks/url.ts b/src/hooks/url.ts
index 07439fdc..fa6a3ddd 100644
--- a/src/hooks/url.ts
+++ b/src/hooks/url.ts
@@ -1,8 +1,8 @@
-import { UrlRouter } from '../url/urlRouter';
-import { StateService } from '../state/stateService';
-import { Transition } from '../transition/transition';
-import { TransitionHookFn } from '../transition/interface';
-import { TransitionService } from '../transition/transitionService';
+import { UrlRouter } from '../url/urlRouter.js';
+import { StateService } from '../state/stateService.js';
+import { Transition } from '../transition/transition.js';
+import { TransitionHookFn } from '../transition/interface.js';
+import { TransitionService } from '../transition/transitionService.js';
 
 /**
  * A [[TransitionHookFn]] which updates the URL after a successful transition
diff --git a/src/hooks/views.ts b/src/hooks/views.ts
index a35771ee..ee0f497a 100644
--- a/src/hooks/views.ts
+++ b/src/hooks/views.ts
@@ -1,10 +1,10 @@
-import { noop } from '../common/common';
-import { services } from '../common/coreservices';
-import { Transition } from '../transition/transition';
-import { ViewService } from '../view/view';
-import { ViewConfig } from '../view/interface';
-import { TransitionHookFn } from '../transition/interface';
-import { TransitionService } from '../transition/transitionService';
+import { noop } from '../common/common.js';
+import { services } from '../common/coreservices.js';
+import { Transition } from '../transition/transition.js';
+import { ViewService } from '../view/view.js';
+import { ViewConfig } from '../view/interface.js';
+import { TransitionHookFn } from '../transition/interface.js';
+import { TransitionService } from '../transition/transitionService.js';
 
 /**
  * A [[TransitionHookFn]] which waits for the views to load
diff --git a/src/index.ts b/src/index.ts
index 470fb7b8..933c8edb 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,13 +1,13 @@
-export * from './common/index';
-export * from './params/index';
-export * from './path/index';
-export * from './resolve/index';
-export * from './state/index';
-export * from './transition/index';
-export * from './url/index';
-export * from './view/index';
-export * from './globals';
+export * from './common/index.js';
+export * from './params/index.js';
+export * from './path/index.js';
+export * from './resolve/index.js';
+export * from './state/index.js';
+export * from './transition/index.js';
+export * from './url/index.js';
+export * from './view/index.js';
+export * from './globals.js';
 
-export * from './router';
-export * from './vanilla';
-export * from './interface';
+export * from './router.js';
+export * from './vanilla.js';
+export * from './interface.js';
diff --git a/src/interface.ts b/src/interface.ts
index 45599217..a750d6dd 100644
--- a/src/interface.ts
+++ b/src/interface.ts
@@ -7,8 +7,8 @@
  * @packageDocumentation
  */
 // Need to import or export at least one concrete something
-import { noop } from './common/common';
-import { UIRouter } from './router';
+import { noop } from './common/common.js';
+import { UIRouter } from './router.js';
 
 /**
  * An interface for getting values from dependency injection.
diff --git a/src/params/index.ts b/src/params/index.ts
index b386de3a..d7ddb406 100644
--- a/src/params/index.ts
+++ b/src/params/index.ts
@@ -5,8 +5,8 @@
  *
  * @packageDocumentation @preferred
  */
-export * from './interface';
-export * from './param';
-export * from './paramTypes';
-export * from './stateParams';
-export * from './paramType';
+export * from './interface.js';
+export * from './param.js';
+export * from './paramTypes.js';
+export * from './stateParams.js';
+export * from './paramType.js';
diff --git a/src/params/interface.ts b/src/params/interface.ts
index a0fe2171..8e944872 100644
--- a/src/params/interface.ts
+++ b/src/params/interface.ts
@@ -1,4 +1,4 @@
-import { ParamType } from './paramType';
+import { ParamType } from './paramType.js';
 
 /**
  * Parameter values
diff --git a/src/params/param.ts b/src/params/param.ts
index c3ef8b29..234c7b11 100644
--- a/src/params/param.ts
+++ b/src/params/param.ts
@@ -1,12 +1,12 @@
-import { extend, filter, map, allTrueR, find } from '../common/common';
-import { prop } from '../common/hof';
-import { isInjectable, isDefined, isString, isArray, isUndefined } from '../common/predicates';
-import { RawParams, ParamDeclaration } from '../params/interface';
-import { services } from '../common/coreservices';
-import { ParamType } from './paramType';
-import { ParamTypes } from './paramTypes';
-import { StateDeclaration } from '../state';
-import { UrlConfig } from '../url';
+import { extend, filter, map, allTrueR, find } from '../common/common.js';
+import { prop } from '../common/hof.js';
+import { isInjectable, isDefined, isString, isArray, isUndefined } from '../common/predicates.js';
+import { RawParams, ParamDeclaration } from '../params/interface.js';
+import { services } from '../common/coreservices.js';
+import { ParamType } from './paramType.js';
+import { ParamTypes } from './paramTypes.js';
+import { StateDeclaration } from '../state/index.js';
+import { UrlConfig } from '../url/index.js';
 
 const hasOwn = Object.prototype.hasOwnProperty;
 
diff --git a/src/params/paramType.ts b/src/params/paramType.ts
index 7b39b3bc..27692067 100644
--- a/src/params/paramType.ts
+++ b/src/params/paramType.ts
@@ -1,6 +1,6 @@
-import { extend, filter, map } from '../common/common';
-import { isArray, isDefined } from '../common/predicates';
-import { ParamTypeDefinition } from './interface';
+import { extend, filter, map } from '../common/common.js';
+import { isArray, isDefined } from '../common/predicates.js';
+import { ParamTypeDefinition } from './interface.js';
 
 /**
  * An internal class which implements [[ParamTypeDefinition]].
diff --git a/src/params/paramTypes.ts b/src/params/paramTypes.ts
index 4abca31a..bf4d5bf1 100644
--- a/src/params/paramTypes.ts
+++ b/src/params/paramTypes.ts
@@ -1,9 +1,9 @@
-import { fromJson, toJson, identity, equals, inherit, map, extend, pick } from '../common/common';
-import { isDefined, isNullOrUndefined } from '../common/predicates';
-import { is } from '../common/hof';
-import { services } from '../common/coreservices';
-import { ParamType } from './paramType';
-import { ParamTypeDefinition } from './interface';
+import { fromJson, toJson, identity, equals, inherit, map, extend, pick } from '../common/common.js';
+import { isDefined, isNullOrUndefined } from '../common/predicates.js';
+import { is } from '../common/hof.js';
+import { services } from '../common/coreservices.js';
+import { ParamType } from './paramType.js';
+import { ParamTypeDefinition } from './interface.js';
 
 /**
  * A registry for parameter types.
diff --git a/src/params/stateParams.ts b/src/params/stateParams.ts
index b79f3893..bb8a3302 100644
--- a/src/params/stateParams.ts
+++ b/src/params/stateParams.ts
@@ -1,6 +1,6 @@
-import { Param } from '.';
-import { extend, ancestors, Obj } from '../common/common';
-import { StateObject } from '../state/stateObject';
+import { Param } from '../index.js';
+import { extend, ancestors, Obj } from '../common/common.js';
+import { StateObject } from '../state/stateObject.js';
 
 export class StateParams {
   [key: string]: any;
diff --git a/src/path/index.ts b/src/path/index.ts
index 02bbf913..270cc7c3 100644
--- a/src/path/index.ts
+++ b/src/path/index.ts
@@ -1,2 +1,2 @@
-export * from './pathNode';
-export * from './pathUtils';
+export * from './pathNode.js';
+export * from './pathUtils.js';
diff --git a/src/path/pathNode.ts b/src/path/pathNode.ts
index d0c54423..b934d5a6 100644
--- a/src/path/pathNode.ts
+++ b/src/path/pathNode.ts
@@ -1,10 +1,10 @@
-import { extend, applyPairs, find, allTrueR, pairs, arrayTuples } from '../common/common';
-import { propEq } from '../common/hof';
-import { StateObject } from '../state/stateObject';
-import { RawParams } from '../params/interface';
-import { Param } from '../params/param';
-import { Resolvable } from '../resolve/resolvable';
-import { ViewConfig } from '../view/interface';
+import { extend, applyPairs, find, allTrueR, pairs, arrayTuples } from '../common/common.js';
+import { propEq } from '../common/hof.js';
+import { StateObject } from '../state/stateObject.js';
+import { RawParams } from '../params/interface.js';
+import { Param } from '../params/param.js';
+import { Resolvable } from '../resolve/resolvable.js';
+import { ViewConfig } from '../view/interface.js';
 
 /**
  * A node in a [[TreeChanges]] path
diff --git a/src/path/pathUtils.ts b/src/path/pathUtils.ts
index 6752d849..01b5440c 100644
--- a/src/path/pathUtils.ts
+++ b/src/path/pathUtils.ts
@@ -10,20 +10,20 @@ import {
   Predicate,
   inArray,
   arrayTuples,
-} from '../common/common';
-import { prop, propEq, not } from '../common/hof';
-
-import { RawParams } from '../params/interface';
-import { TreeChanges } from '../transition/interface';
-import { ViewConfig } from '../view/interface';
-import { _ViewDeclaration } from '../state/interface';
-
-import { StateObject } from '../state/stateObject';
-import { TargetState } from '../state/targetState';
-import { GetParamsFn, PathNode } from './pathNode';
-import { ViewService } from '../view/view';
-import { Param } from '../params/param';
-import { StateRegistry } from '../state';
+} from '../common/common.js';
+import { prop, propEq, not } from '../common/hof.js';
+
+import { RawParams } from '../params/interface.js';
+import { TreeChanges } from '../transition/interface.js';
+import { ViewConfig } from '../view/interface.js';
+import { _ViewDeclaration } from '../state/interface.js';
+
+import { StateObject } from '../state/stateObject.js';
+import { TargetState } from '../state/targetState.js';
+import { GetParamsFn, PathNode } from './pathNode.js';
+import { ViewService } from '../view/view.js';
+import { Param } from '../params/param.js';
+import { StateRegistry } from '../state/index.js';
 
 /**
  * This class contains functions which convert TargetStates, Nodes and paths from one type to another.
diff --git a/src/resolve/index.ts b/src/resolve/index.ts
index b54145a2..da23833a 100644
--- a/src/resolve/index.ts
+++ b/src/resolve/index.ts
@@ -1,3 +1,3 @@
-export * from './interface';
-export * from './resolvable';
-export * from './resolveContext';
+export * from './interface.js';
+export * from './resolvable.js';
+export * from './resolveContext.js';
diff --git a/src/resolve/resolvable.ts b/src/resolve/resolvable.ts
index d665ba04..c9a9b186 100644
--- a/src/resolve/resolvable.ts
+++ b/src/resolve/resolvable.ts
@@ -1,15 +1,15 @@
-import { extend, identity } from '../common/common';
-import { services } from '../common/coreservices';
-import { trace } from '../common/trace';
-import { ResolvePolicy, ResolvableLiteral, PolicyAsync } from './interface';
-
-import { ResolveContext } from './resolveContext';
-import { stringify } from '../common/strings';
-import { isFunction, isObject } from '../common/predicates';
-import { Transition } from '../transition/transition';
-import { StateObject } from '../state/stateObject';
-import { PathNode } from '../path/pathNode';
-import { isNullOrUndefined } from '../common/predicates';
+import { extend, identity } from '../common/common.js';
+import { services } from '../common/coreservices.js';
+import { trace } from '../common/trace.js';
+import { ResolvePolicy, ResolvableLiteral, PolicyAsync } from './interface.js';
+
+import { ResolveContext } from './resolveContext.js';
+import { stringify } from '../common/strings.js';
+import { isFunction, isObject } from '../common/predicates.js';
+import { Transition } from '../transition/transition.js';
+import { StateObject } from '../state/stateObject.js';
+import { PathNode } from '../path/pathNode.js';
+import { isNullOrUndefined } from '../common/predicates.js';
 
 // TODO: explicitly make this user configurable
 export let defaultResolvePolicy: ResolvePolicy = {
diff --git a/src/resolve/resolveContext.ts b/src/resolve/resolveContext.ts
index 01202497..76f3a467 100644
--- a/src/resolve/resolveContext.ts
+++ b/src/resolve/resolveContext.ts
@@ -1,16 +1,16 @@
-import { find, tail, uniqR, unnestR, inArray } from '../common/common';
-import { propEq, not } from '../common/hof';
-import { trace } from '../common/trace';
-import { services, $InjectorLike } from '../common/coreservices';
-import { resolvePolicies, PolicyWhen, ResolvePolicy } from './interface';
-import { PathNode } from '../path/pathNode';
-import { Resolvable } from './resolvable';
-import { StateObject } from '../state/stateObject';
-import { PathUtils } from '../path/pathUtils';
-import { stringify } from '../common/strings';
-import { Transition } from '../transition/transition';
-import { UIInjector } from '../interface';
-import { isUndefined } from '../common';
+import { find, tail, uniqR, unnestR, inArray } from '../common/common.js';
+import { propEq, not } from '../common/hof.js';
+import { trace } from '../common/trace.js';
+import { services, $InjectorLike } from '../common/coreservices.js';
+import { resolvePolicies, PolicyWhen, ResolvePolicy } from './interface.js';
+import { PathNode } from '../path/pathNode.js';
+import { Resolvable } from './resolvable.js';
+import { StateObject } from '../state/stateObject.js';
+import { PathUtils } from '../path/pathUtils.js';
+import { stringify } from '../common/strings.js';
+import { Transition } from '../transition/transition.js';
+import { UIInjector } from '../interface.js';
+import { isUndefined } from '../common/index.js';
 
 const whens = resolvePolicies.when;
 const ALL_WHENS = [whens.EAGER, whens.LAZY];
diff --git a/src/router.ts b/src/router.ts
index 46b9daa2..eaa5d13d 100644
--- a/src/router.ts
+++ b/src/router.ts
@@ -1,17 +1,17 @@
-import { UrlMatcherFactory } from './url/urlMatcherFactory';
-import { UrlRouter } from './url/urlRouter';
-import { TransitionService } from './transition/transitionService';
-import { ViewService } from './view/view';
-import { StateRegistry } from './state/stateRegistry';
-import { StateService } from './state/stateService';
-import { UIRouterGlobals } from './globals';
-import { UIRouterPlugin, Disposable } from './interface';
-import { values, removeFrom } from './common/common';
-import { isFunction } from './common/predicates';
-import { UrlService } from './url/urlService';
-import { LocationServices, LocationConfig } from './common/coreservices';
-import { Trace, trace } from './common/trace';
-import { makeStub } from './common';
+import { UrlMatcherFactory } from './url/urlMatcherFactory.js';
+import { UrlRouter } from './url/urlRouter.js';
+import { TransitionService } from './transition/transitionService.js';
+import { ViewService } from './view/view.js';
+import { StateRegistry } from './state/stateRegistry.js';
+import { StateService } from './state/stateService.js';
+import { UIRouterGlobals } from './globals.js';
+import { UIRouterPlugin, Disposable } from './interface.js';
+import { values, removeFrom } from './common/common.js';
+import { isFunction } from './common/predicates.js';
+import { UrlService } from './url/urlService.js';
+import { LocationServices, LocationConfig } from './common/coreservices.js';
+import { Trace, trace } from './common/trace.js';
+import { makeStub } from './common/index.js';
 
 /** @internal */
 let _routerInstance = 0;
diff --git a/src/state/index.ts b/src/state/index.ts
index 79cf0995..f741a4ed 100644
--- a/src/state/index.ts
+++ b/src/state/index.ts
@@ -18,11 +18,11 @@
  *
  * @packageDocumentation
  */
-export * from './interface';
-export * from './stateBuilder';
-export * from './stateObject';
-export * from './stateMatcher';
-export * from './stateQueueManager';
-export * from './stateRegistry';
-export * from './stateService';
-export * from './targetState';
+export * from './interface.js';
+export * from './stateBuilder.js';
+export * from './stateObject.js';
+export * from './stateMatcher.js';
+export * from './stateQueueManager.js';
+export * from './stateRegistry.js';
+export * from './stateService.js';
+export * from './targetState.js';
diff --git a/src/state/interface.ts b/src/state/interface.ts
index 3188dbc0..996bd004 100644
--- a/src/state/interface.ts
+++ b/src/state/interface.ts
@@ -1,12 +1,12 @@
-import { ParamDeclaration, RawParams } from '../params/interface';
-import { StateObject } from './stateObject';
-import { ViewContext } from '../view/interface';
-import { IInjectable } from '../common/common';
-import { Transition } from '../transition/transition';
-import { TransitionStateHookFn, TransitionOptions } from '../transition/interface';
-import { ResolvePolicy, ResolvableLiteral, ProviderLike } from '../resolve/interface';
-import { Resolvable } from '../resolve/resolvable';
-import { TargetState } from './targetState';
+import { ParamDeclaration, RawParams } from '../params/interface.js';
+import { StateObject } from './stateObject.js';
+import { ViewContext } from '../view/interface.js';
+import { IInjectable } from '../common/common.js';
+import { Transition } from '../transition/transition.js';
+import { TransitionStateHookFn, TransitionOptions } from '../transition/interface.js';
+import { ResolvePolicy, ResolvableLiteral, ProviderLike } from '../resolve/interface.js';
+import { Resolvable } from '../resolve/resolvable.js';
+import { TargetState } from './targetState.js';
 
 export type StateOrName = string | StateDeclaration | StateObject;
 
diff --git a/src/state/stateBuilder.ts b/src/state/stateBuilder.ts
index 6a2dca34..627d57f1 100644
--- a/src/state/stateBuilder.ts
+++ b/src/state/stateBuilder.ts
@@ -1,19 +1,31 @@
-import { applyPairs, extend, identity, inherit, mapObj, noop, Obj, omit, tail, values, copy } from '../common/common';
-import { isArray, isDefined, isFunction, isString } from '../common/predicates';
-import { stringify } from '../common/strings';
-import { is, pattern, pipe, prop, val } from '../common/hof';
-import { StateDeclaration } from './interface';
-
-import { StateObject } from './stateObject';
-import { StateMatcher } from './stateMatcher';
-import { Param } from '../params/param';
-import { UrlMatcherFactory } from '../url/urlMatcherFactory';
-import { UrlMatcher } from '../url/urlMatcher';
-import { Resolvable } from '../resolve/resolvable';
-import { services } from '../common/coreservices';
-import { ResolvePolicy } from '../resolve/interface';
-import { ParamDeclaration } from '../params';
-import { ParamFactory } from '../url';
+import {
+  applyPairs,
+  extend,
+  identity,
+  inherit,
+  mapObj,
+  noop,
+  Obj,
+  omit,
+  tail,
+  values,
+  copy,
+} from '../common/common.js';
+import { isArray, isDefined, isFunction, isString } from '../common/predicates.js';
+import { stringify } from '../common/strings.js';
+import { is, pattern, pipe, prop, val } from '../common/hof.js';
+import { StateDeclaration } from './interface.js';
+
+import { StateObject } from './stateObject.js';
+import { StateMatcher } from './stateMatcher.js';
+import { Param } from '../params/param.js';
+import { UrlMatcherFactory } from '../url/urlMatcherFactory.js';
+import { UrlMatcher } from '../url/urlMatcher.js';
+import { Resolvable } from '../resolve/resolvable.js';
+import { services } from '../common/coreservices.js';
+import { ResolvePolicy } from '../resolve/interface.js';
+import { ParamDeclaration } from '../params/index.js';
+import { ParamFactory } from '../url/index.js';
 
 const parseUrl = (url: string): any => {
   if (!isString(url)) return false;
diff --git a/src/state/stateMatcher.ts b/src/state/stateMatcher.ts
index ee572b65..4d718161 100644
--- a/src/state/stateMatcher.ts
+++ b/src/state/stateMatcher.ts
@@ -1,8 +1,8 @@
-import { isString } from '../common/predicates';
-import { StateOrName } from './interface';
-import { StateObject } from './stateObject';
-import { values } from '../common/common';
-import { safeConsole } from '../common/safeConsole';
+import { isString } from '../common/predicates.js';
+import { StateOrName } from './interface.js';
+import { StateObject } from './stateObject.js';
+import { values } from '../common/common.js';
+import { safeConsole } from '../common/safeConsole.js';
 
 export class StateMatcher {
   constructor(private _states: { [key: string]: StateObject }) {}
diff --git a/src/state/stateObject.ts b/src/state/stateObject.ts
index cb6f4406..2e0f44e7 100644
--- a/src/state/stateObject.ts
+++ b/src/state/stateObject.ts
@@ -1,14 +1,14 @@
-import { StateDeclaration, _ViewDeclaration, _StateDeclaration, LazyLoadResult } from './interface';
-import { defaults, values, find, inherit } from '../common/common';
-import { propEq } from '../common/hof';
-import { Param } from '../params/param';
-import { UrlMatcher } from '../url/urlMatcher';
-import { Resolvable } from '../resolve/resolvable';
-import { TransitionStateHookFn } from '../transition/interface';
-import { TargetState } from './targetState';
-import { Transition } from '../transition/transition';
-import { Glob } from '../common/glob';
-import { isObject, isFunction } from '../common/predicates';
+import { StateDeclaration, _ViewDeclaration, _StateDeclaration, LazyLoadResult } from './interface.js';
+import { defaults, values, find, inherit } from '../common/common.js';
+import { propEq } from '../common/hof.js';
+import { Param } from '../params/param.js';
+import { UrlMatcher } from '../url/urlMatcher.js';
+import { Resolvable } from '../resolve/resolvable.js';
+import { TransitionStateHookFn } from '../transition/interface.js';
+import { TargetState } from './targetState.js';
+import { Transition } from '../transition/transition.js';
+import { Glob } from '../common/glob.js';
+import { isObject, isFunction } from '../common/predicates.js';
 
 /**
  * Internal representation of a UI-Router state.
diff --git a/src/state/stateQueueManager.ts b/src/state/stateQueueManager.ts
index d7ca75f3..d5c9b15d 100644
--- a/src/state/stateQueueManager.ts
+++ b/src/state/stateQueueManager.ts
@@ -1,10 +1,10 @@
-import { inArray, isString, prop } from '../common';
-import { _StateDeclaration } from './interface';
-import { StateObject } from './stateObject';
-import { StateBuilder } from './stateBuilder';
-import { StateRegistryListener } from './stateRegistry';
-import { Disposable } from '../interface';
-import { UIRouter } from '../router';
+import { inArray, isString, prop } from '../common/index.js';
+import { _StateDeclaration } from './interface.js';
+import { StateObject } from './stateObject.js';
+import { StateBuilder } from './stateBuilder.js';
+import { StateRegistryListener } from './stateRegistry.js';
+import { Disposable } from '../interface.js';
+import { UIRouter } from '../router.js';
 
 export class StateQueueManager implements Disposable {
   queue: StateObject[] = [];
diff --git a/src/state/stateRegistry.ts b/src/state/stateRegistry.ts
index e6ab1a9d..ee423dc4 100644
--- a/src/state/stateRegistry.ts
+++ b/src/state/stateRegistry.ts
@@ -1,13 +1,13 @@
-import { StateObject } from './stateObject';
-import { StateMatcher } from './stateMatcher';
-import { StateBuilder } from './stateBuilder';
-import { StateQueueManager } from './stateQueueManager';
-import { StateDeclaration, _StateDeclaration } from './interface';
-import { BuilderFunction } from './stateBuilder';
-import { StateOrName } from './interface';
-import { removeFrom } from '../common/common';
-import { UIRouter } from '../router';
-import { propEq } from '../common/hof';
+import { StateObject } from './stateObject.js';
+import { StateMatcher } from './stateMatcher.js';
+import { StateBuilder } from './stateBuilder.js';
+import { StateQueueManager } from './stateQueueManager.js';
+import { StateDeclaration, _StateDeclaration } from './interface.js';
+import { BuilderFunction } from './stateBuilder.js';
+import { StateOrName } from './interface.js';
+import { removeFrom } from '../common/common.js';
+import { UIRouter } from '../router.js';
+import { propEq } from '../common/hof.js';
 
 /**
  * The signature for the callback function provided to [[StateRegistry.onStatesChanged]].
diff --git a/src/state/stateService.ts b/src/state/stateService.ts
index e7d46333..c6eedd85 100644
--- a/src/state/stateService.ts
+++ b/src/state/stateService.ts
@@ -7,32 +7,32 @@ import {
   removeFrom,
   silenceUncaughtInPromise,
   silentRejection,
-} from '../common/common';
-import { isDefined, isObject, isString } from '../common/predicates';
-import { Queue } from '../common/queue';
-import { services } from '../common/coreservices';
-
-import { PathUtils } from '../path/pathUtils';
-import { PathNode } from '../path/pathNode';
-
-import { HookResult, TransitionOptions } from '../transition/interface';
-import { defaultTransOpts } from '../transition/transitionService';
-import { Rejection, RejectType } from '../transition/rejectFactory';
-import { Transition } from '../transition/transition';
-
-import { HrefOptions, LazyLoadResult, StateDeclaration, StateOrName, TransitionPromise } from './interface';
-import { StateObject } from './stateObject';
-import { TargetState } from './targetState';
-
-import { RawParams } from '../params/interface';
-import { Param } from '../params/param';
-import { Glob } from '../common/glob';
-import { UIRouter } from '../router';
-import { UIInjector } from '../interface';
-import { ResolveContext } from '../resolve/resolveContext';
-import { lazyLoadState } from '../hooks/lazyLoad';
-import { not, val } from '../common/hof';
-import { StateParams } from '../params/stateParams';
+} from '../common/common.js';
+import { isDefined, isObject, isString } from '../common/predicates.js';
+import { Queue } from '../common/queue.js';
+import { services } from '../common/coreservices.js';
+
+import { PathUtils } from '../path/pathUtils.js';
+import { PathNode } from '../path/pathNode.js';
+
+import { HookResult, TransitionOptions } from '../transition/interface.js';
+import { defaultTransOpts } from '../transition/transitionService.js';
+import { Rejection, RejectType } from '../transition/rejectFactory.js';
+import { Transition } from '../transition/transition.js';
+
+import { HrefOptions, LazyLoadResult, StateDeclaration, StateOrName, TransitionPromise } from './interface.js';
+import { StateObject } from './stateObject.js';
+import { TargetState } from './targetState.js';
+
+import { RawParams } from '../params/interface.js';
+import { Param } from '../params/param.js';
+import { Glob } from '../common/glob.js';
+import { UIRouter } from '../router.js';
+import { UIInjector } from '../interface.js';
+import { ResolveContext } from '../resolve/resolveContext.js';
+import { lazyLoadState } from '../hooks/lazyLoad.js';
+import { not, val } from '../common/hof.js';
+import { StateParams } from '../params/stateParams.js';
 
 export type OnInvalidCallback = (toState?: TargetState, fromState?: TargetState, injector?: UIInjector) => HookResult;
 
@@ -354,35 +354,37 @@ export class StateService {
      * no error occurred.  Likewise, the transition.run() promise may be rejected because of
      * a Redirect, but the transitionTo() promise is chained to the new Transition's promise.
      */
-    const rejectedTransitionHandler = (trans: Transition) => (error: any): Promise<any> => {
-      if (error instanceof Rejection) {
-        const isLatest = router.globals.lastStartedTransitionId <= trans.$id;
-
-        if (error.type === RejectType.IGNORED) {
-          isLatest && router.urlRouter.update();
-          // Consider ignored `Transition.run()` as a successful `transitionTo`
-          return services.$q.when(globals.current);
+    const rejectedTransitionHandler =
+      (trans: Transition) =>
+      (error: any): Promise<any> => {
+        if (error instanceof Rejection) {
+          const isLatest = router.globals.lastStartedTransitionId <= trans.$id;
+
+          if (error.type === RejectType.IGNORED) {
+            isLatest && router.urlRouter.update();
+            // Consider ignored `Transition.run()` as a successful `transitionTo`
+            return services.$q.when(globals.current);
+          }
+
+          const detail: any = error.detail;
+          if (error.type === RejectType.SUPERSEDED && error.redirected && detail instanceof TargetState) {
+            // If `Transition.run()` was redirected, allow the `transitionTo()` promise to resolve successfully
+            // by returning the promise for the new (redirect) `Transition.run()`.
+            const redirect: Transition = trans.redirect(detail);
+            return redirect.run().catch(rejectedTransitionHandler(redirect));
+          }
+
+          if (error.type === RejectType.ABORTED) {
+            isLatest && router.urlRouter.update();
+            return services.$q.reject(error);
+          }
         }
 
-        const detail: any = error.detail;
-        if (error.type === RejectType.SUPERSEDED && error.redirected && detail instanceof TargetState) {
-          // If `Transition.run()` was redirected, allow the `transitionTo()` promise to resolve successfully
-          // by returning the promise for the new (redirect) `Transition.run()`.
-          const redirect: Transition = trans.redirect(detail);
-          return redirect.run().catch(rejectedTransitionHandler(redirect));
-        }
-
-        if (error.type === RejectType.ABORTED) {
-          isLatest && router.urlRouter.update();
-          return services.$q.reject(error);
-        }
-      }
-
-      const errorHandler = this.defaultErrorHandler();
-      errorHandler(error);
+        const errorHandler = this.defaultErrorHandler();
+        errorHandler(error);
 
-      return services.$q.reject(error);
-    };
+        return services.$q.reject(error);
+      };
 
     const transition = this.router.transitionService.create(currentPath, ref);
     const transitionToPromise = transition.run().catch(rejectedTransitionHandler(transition));
diff --git a/src/state/targetState.ts b/src/state/targetState.ts
index cd03140a..707b0936 100644
--- a/src/state/targetState.ts
+++ b/src/state/targetState.ts
@@ -1,11 +1,11 @@
-import { StateDeclaration, StateOrName, TargetStateDef } from './interface';
-import { TransitionOptions } from '../transition/interface';
-import { StateObject } from './stateObject';
-import { isObject, isString } from '../common/predicates';
-import { stringify } from '../common/strings';
-import { extend } from '../common';
-import { StateRegistry } from './stateRegistry';
-import { RawParams } from '../params';
+import { StateDeclaration, StateOrName, TargetStateDef } from './interface.js';
+import { TransitionOptions } from '../transition/interface.js';
+import { StateObject } from './stateObject.js';
+import { isObject, isString } from '../common/predicates.js';
+import { stringify } from '../common/strings.js';
+import { extend } from '../common/index.js';
+import { StateRegistry } from './stateRegistry.js';
+import { RawParams } from '../params/index.js';
 
 /**
  * Encapsulate the target (destination) state/params/options of a [[Transition]].
diff --git a/src/transition/hookBuilder.ts b/src/transition/hookBuilder.ts
index 6f479708..22abde20 100644
--- a/src/transition/hookBuilder.ts
+++ b/src/transition/hookBuilder.ts
@@ -1,5 +1,5 @@
-import { extend, tail, assertPredicate, unnestR, identity } from '../common/common';
-import { isArray } from '../common/predicates';
+import { extend, tail, assertPredicate, unnestR, identity } from '../common/common.js';
+import { isArray } from '../common/predicates.js';
 
 import {
   TransitionOptions,
@@ -9,15 +9,15 @@ import {
   IMatchingNodes,
   TransitionHookPhase,
   TransitionHookScope,
-} from './interface';
-
-import { Transition } from './transition';
-import { TransitionHook } from './transitionHook';
-import { StateObject } from '../state/stateObject';
-import { PathNode } from '../path/pathNode';
-import { TransitionService } from './transitionService';
-import { TransitionEventType } from './transitionEventType';
-import { RegisteredHook } from './hookRegistry';
+} from './interface.js';
+
+import { Transition } from './transition.js';
+import { TransitionHook } from './transitionHook.js';
+import { StateObject } from '../state/stateObject.js';
+import { PathNode } from '../path/pathNode.js';
+import { TransitionService } from './transitionService.js';
+import { TransitionEventType } from './transitionEventType.js';
+import { RegisteredHook } from './hookRegistry.js';
 
 /**
  * This class returns applicable TransitionHooks for a specific Transition instance.
diff --git a/src/transition/hookRegistry.ts b/src/transition/hookRegistry.ts
index fd798317..e4f19638 100644
--- a/src/transition/hookRegistry.ts
+++ b/src/transition/hookRegistry.ts
@@ -1,5 +1,5 @@
-import { isString, isFunction, Glob, extend, removeFrom, tail, values, identity, mapObj } from '../common';
-import { PathNode } from '../path/pathNode';
+import { isString, isFunction, Glob, extend, removeFrom, tail, values, identity, mapObj } from '../common/index.js';
+import { PathNode } from '../path/pathNode.js';
 import {
   TransitionStateHookFn,
   TransitionHookFn,
@@ -7,7 +7,7 @@ import {
   TransitionHookScope,
   IHookRegistry,
   PathType,
-} from './interface';
+} from './interface.js';
 
 import {
   HookRegOptions,
@@ -16,11 +16,11 @@ import {
   HookMatchCriterion,
   IMatchingNodes,
   HookFn,
-} from './interface';
-import { Transition } from './transition';
-import { StateObject } from '../state/stateObject';
-import { TransitionEventType } from './transitionEventType';
-import { TransitionService } from './transitionService';
+} from './interface.js';
+import { Transition } from './transition.js';
+import { StateObject } from '../state/stateObject.js';
+import { TransitionEventType } from './transitionEventType.js';
+import { TransitionService } from './transitionService.js';
 
 /**
  * Determines if the given state matches the matchCriteria
diff --git a/src/transition/index.ts b/src/transition/index.ts
index 56312da3..8147a4cd 100644
--- a/src/transition/index.ts
+++ b/src/transition/index.ts
@@ -10,11 +10,11 @@
  *
  * @packageDocumentation @preferred
  */
-export * from './interface';
-export * from './hookBuilder';
-export * from './hookRegistry';
-export * from './rejectFactory';
-export * from './transition';
-export * from './transitionHook';
-export * from './transitionEventType';
-export * from './transitionService';
+export * from './interface.js';
+export * from './hookBuilder.js';
+export * from './hookRegistry.js';
+export * from './rejectFactory.js';
+export * from './transition.js';
+export * from './transitionHook.js';
+export * from './transitionEventType.js';
+export * from './transitionService.js';
diff --git a/src/transition/interface.ts b/src/transition/interface.ts
index 854bc53d..16056a15 100644
--- a/src/transition/interface.ts
+++ b/src/transition/interface.ts
@@ -1,11 +1,11 @@
-import { StateDeclaration } from '../state/interface';
-import { PredicateBinary } from '../common/common';
-
-import { Transition } from './transition';
-import { StateObject } from '../state/stateObject';
-import { PathNode } from '../path/pathNode';
-import { TargetState } from '../state/targetState';
-import { RegisteredHook } from './hookRegistry';
+import { StateDeclaration } from '../state/interface.js';
+import { PredicateBinary } from '../common/common.js';
+
+import { Transition } from './transition.js';
+import { StateObject } from '../state/stateObject.js';
+import { PathNode } from '../path/pathNode.js';
+import { TargetState } from '../state/targetState.js';
+import { RegisteredHook } from './hookRegistry.js';
 
 /**
  * The TransitionOptions object can be used to change the behavior of a transition.
diff --git a/src/transition/rejectFactory.ts b/src/transition/rejectFactory.ts
index 6a287365..f9ae30fb 100644
--- a/src/transition/rejectFactory.ts
+++ b/src/transition/rejectFactory.ts
@@ -1,7 +1,7 @@
 'use strict';
-import { extend, silentRejection } from '../common/common';
-import { stringify } from '../common/strings';
-import { is } from '../common/hof';
+import { extend, silentRejection } from '../common/common.js';
+import { stringify } from '../common/strings.js';
+import { is } from '../common/hof.js';
 
 /** An enum for Transition Rejection reasons */
 enum RejectType {
diff --git a/src/transition/transition.ts b/src/transition/transition.ts
index 79680cc5..6050bbd1 100644
--- a/src/transition/transition.ts
+++ b/src/transition/transition.ts
@@ -1,10 +1,10 @@
-import { trace } from '../common/trace';
-import { services } from '../common/coreservices';
-import { stringify } from '../common/strings';
-import { map, find, extend, mergeR, tail, omit, arrayTuples, unnestR, identity, anyTrueR } from '../common/common';
-import { isObject, isUndefined } from '../common/predicates';
-import { prop, propEq, val, not, is } from '../common/hof';
-import { StateDeclaration, StateOrName } from '../state/interface';
+import { trace } from '../common/trace.js';
+import { services } from '../common/coreservices.js';
+import { stringify } from '../common/strings.js';
+import { map, find, extend, mergeR, tail, omit, arrayTuples, unnestR, identity, anyTrueR } from '../common/common.js';
+import { isObject, isUndefined } from '../common/predicates.js';
+import { prop, propEq, val, not, is } from '../common/hof.js';
+import { StateDeclaration, StateOrName } from '../state/interface.js';
 import {
   TransitionOptions,
   TreeChanges,
@@ -15,24 +15,24 @@ import {
   HookMatchCriteria,
   TransitionStateHookFn,
   TransitionHookFn,
-} from './interface'; // has or is using
-import { TransitionHook } from './transitionHook';
-import { matchState, makeEvent, RegisteredHook } from './hookRegistry';
-import { HookBuilder } from './hookBuilder';
-import { PathNode } from '../path/pathNode';
-import { PathUtils } from '../path/pathUtils';
-import { StateObject } from '../state/stateObject';
-import { TargetState } from '../state/targetState';
-import { Param } from '../params/param';
-import { Resolvable } from '../resolve/resolvable';
-import { ViewConfig } from '../view/interface';
-import { ResolveContext } from '../resolve/resolveContext';
-import { UIRouter } from '../router';
-import { UIInjector } from '../interface';
-import { RawParams } from '../params/interface';
-import { ResolvableLiteral } from '../resolve/interface';
-import { Rejection } from './rejectFactory';
-import { applyPairs, flattenR, uniqR } from '../common';
+} from './interface.js'; // has or is using
+import { TransitionHook } from './transitionHook.js';
+import { matchState, makeEvent, RegisteredHook } from './hookRegistry.js';
+import { HookBuilder } from './hookBuilder.js';
+import { PathNode } from '../path/pathNode.js';
+import { PathUtils } from '../path/pathUtils.js';
+import { StateObject } from '../state/stateObject.js';
+import { TargetState } from '../state/targetState.js';
+import { Param } from '../params/param.js';
+import { Resolvable } from '../resolve/resolvable.js';
+import { ViewConfig } from '../view/interface.js';
+import { ResolveContext } from '../resolve/resolveContext.js';
+import { UIRouter } from '../router.js';
+import { UIInjector } from '../interface.js';
+import { RawParams } from '../params/interface.js';
+import { ResolvableLiteral } from '../resolve/interface.js';
+import { Rejection } from './rejectFactory.js';
+import { applyPairs, flattenR, uniqR } from '../common/index.js';
 
 /** @internal */
 const stateSelf: (_state: StateObject) => StateDeclaration = prop('self');
diff --git a/src/transition/transitionEventType.ts b/src/transition/transitionEventType.ts
index 4b3b6401..7bd43989 100644
--- a/src/transition/transitionEventType.ts
+++ b/src/transition/transitionEventType.ts
@@ -1,5 +1,5 @@
-import { TransitionHookPhase, PathType } from './interface';
-import { GetErrorHandler, GetResultHandler, TransitionHook } from './transitionHook';
+import { TransitionHookPhase, PathType } from './interface.js';
+import { GetErrorHandler, GetResultHandler, TransitionHook } from './transitionHook.js';
 /**
  * This class defines a type of hook, such as `onBefore` or `onEnter`.
  * Plugins can define custom hook types, such as sticky states does for `onInactive`.
diff --git a/src/transition/transitionHook.ts b/src/transition/transitionHook.ts
index 8b31f47e..8ecac89c 100644
--- a/src/transition/transitionHook.ts
+++ b/src/transition/transitionHook.ts
@@ -1,16 +1,16 @@
-import { TransitionHookOptions, HookResult, TransitionHookPhase } from './interface';
-import { defaults, noop, silentRejection } from '../common/common';
-import { fnToString, maxLength } from '../common/strings';
-import { isPromise } from '../common/predicates';
-import { is, parse } from '../common/hof';
-import { trace } from '../common/trace';
-import { services } from '../common/coreservices';
-import { Rejection } from './rejectFactory';
-import { TargetState } from '../state/targetState';
-import { Transition } from './transition';
-import { TransitionEventType } from './transitionEventType';
-import { RegisteredHook } from './hookRegistry';
-import { StateDeclaration } from '../state/interface';
+import { TransitionHookOptions, HookResult, TransitionHookPhase } from './interface.js';
+import { defaults, noop, silentRejection } from '../common/common.js';
+import { fnToString, maxLength } from '../common/strings.js';
+import { isPromise } from '../common/predicates.js';
+import { is, parse } from '../common/hof.js';
+import { trace } from '../common/trace.js';
+import { services } from '../common/coreservices.js';
+import { Rejection } from './rejectFactory.js';
+import { TargetState } from '../state/targetState.js';
+import { Transition } from './transition.js';
+import { TransitionEventType } from './transitionEventType.js';
+import { RegisteredHook } from './hookRegistry.js';
+import { StateDeclaration } from '../state/interface.js';
 
 const defaultOptions: TransitionHookOptions = {
   current: noop,
diff --git a/src/transition/transitionService.ts b/src/transition/transitionService.ts
index 22b91ee5..4ccec38c 100644
--- a/src/transition/transitionService.ts
+++ b/src/transition/transitionService.ts
@@ -11,29 +11,29 @@ import {
   RegisteredHooks,
   TransitionHookFn,
   TransitionStateHookFn,
-} from './interface';
-import { Transition } from './transition';
-import { makeEvent, RegisteredHook } from './hookRegistry';
-import { TargetState } from '../state/targetState';
-import { PathNode } from '../path/pathNode';
-import { ViewService } from '../view/view';
-import { UIRouter } from '../router';
-import { registerAddCoreResolvables, treeChangesCleanup } from '../hooks/coreResolvables';
-import { registerRedirectToHook } from '../hooks/redirectTo';
-import { registerOnExitHook, registerOnRetainHook, registerOnEnterHook } from '../hooks/onEnterExitRetain';
-import { registerEagerResolvePath, registerLazyResolveState, registerResolveRemaining } from '../hooks/resolve';
-import { registerLoadEnteringViews, registerActivateViews } from '../hooks/views';
-import { registerUpdateGlobalState } from '../hooks/updateGlobals';
-import { registerUpdateUrl } from '../hooks/url';
-import { registerLazyLoadHook } from '../hooks/lazyLoad';
-import { TransitionEventType } from './transitionEventType';
-import { TransitionHook, GetResultHandler, GetErrorHandler } from './transitionHook';
-import { isDefined } from '../common/predicates';
-import { removeFrom, values, createProxyFunctions } from '../common/common';
-import { Disposable } from '../interface'; // has or is using
-import { val } from '../common/hof';
-import { registerIgnoredTransitionHook } from '../hooks/ignoredTransition';
-import { registerInvalidTransitionHook } from '../hooks/invalidTransition';
+} from './interface.js';
+import { Transition } from './transition.js';
+import { makeEvent, RegisteredHook } from './hookRegistry.js';
+import { TargetState } from '../state/targetState.js';
+import { PathNode } from '../path/pathNode.js';
+import { ViewService } from '../view/view.js';
+import { UIRouter } from '../router.js';
+import { registerAddCoreResolvables, treeChangesCleanup } from '../hooks/coreResolvables.js';
+import { registerRedirectToHook } from '../hooks/redirectTo.js';
+import { registerOnExitHook, registerOnRetainHook, registerOnEnterHook } from '../hooks/onEnterExitRetain.js';
+import { registerEagerResolvePath, registerLazyResolveState, registerResolveRemaining } from '../hooks/resolve.js';
+import { registerLoadEnteringViews, registerActivateViews } from '../hooks/views.js';
+import { registerUpdateGlobalState } from '../hooks/updateGlobals.js';
+import { registerUpdateUrl } from '../hooks/url.js';
+import { registerLazyLoadHook } from '../hooks/lazyLoad.js';
+import { TransitionEventType } from './transitionEventType.js';
+import { TransitionHook, GetResultHandler, GetErrorHandler } from './transitionHook.js';
+import { isDefined } from '../common/predicates.js';
+import { removeFrom, values, createProxyFunctions } from '../common/common.js';
+import { Disposable } from '../interface.js'; // has or is using
+import { val } from '../common/hof.js';
+import { registerIgnoredTransitionHook } from '../hooks/ignoredTransition.js';
+import { registerInvalidTransitionHook } from '../hooks/invalidTransition.js';
 
 /**
  * The default [[Transition]] options.
diff --git a/src/url/index.ts b/src/url/index.ts
index fb1896e4..7d136be6 100644
--- a/src/url/index.ts
+++ b/src/url/index.ts
@@ -1,8 +1,8 @@
-export * from './interface';
-export * from './urlMatcher';
-export * from './urlMatcherFactory';
-export * from './urlRouter';
-export * from './urlRule';
-export * from './urlService';
-export { UrlRules } from './urlRules';
-export { UrlConfig } from './urlConfig';
+export * from './interface.js';
+export * from './urlMatcher.js';
+export * from './urlMatcherFactory.js';
+export * from './urlRouter.js';
+export * from './urlRule.js';
+export * from './urlService.js';
+export { UrlRules } from './urlRules.js';
+export { UrlConfig } from './urlConfig.js';
diff --git a/src/url/interface.ts b/src/url/interface.ts
index 1e010030..f4cf7bc5 100644
--- a/src/url/interface.ts
+++ b/src/url/interface.ts
@@ -8,13 +8,13 @@
  * @packageDocumentation
  * @preferred
  */
-import { LocationConfig } from '../common';
-import { UIRouter } from '../router';
-import { StateDeclaration, StateObject, TargetState, TargetStateDef } from '../state';
-import { UrlMatcher } from './urlMatcher';
-import { UrlConfig } from './urlConfig';
-import { UrlRules } from './urlRules';
-import { UrlService } from './urlService';
+import { LocationConfig } from '../common/index.js';
+import { UIRouter } from '../router.js';
+import { StateDeclaration, StateObject, TargetState, TargetStateDef } from '../state/index.js';
+import { UrlMatcher } from './urlMatcher.js';
+import { UrlConfig } from './urlConfig.js';
+import { UrlRules } from './urlRules.js';
+import { UrlService } from './urlService.js';
 
 export interface UrlMatcherCompileConfig {
   // If state is provided, use the configuration in the `params` block
diff --git a/src/url/urlConfig.ts b/src/url/urlConfig.ts
index 613f8c5f..4ff0d640 100644
--- a/src/url/urlConfig.ts
+++ b/src/url/urlConfig.ts
@@ -1,7 +1,7 @@
-import { Disposable } from '../interface';
-import { UIRouter } from '../router';
-import { ParamTypeDefinition, ParamTypes } from '../params';
-import { isDefined, isString } from '../common';
+import { Disposable } from '../interface.js';
+import { UIRouter } from '../router.js';
+import { ParamTypeDefinition, ParamTypes } from '../params/index.js';
+import { isDefined, isString } from '../common/index.js';
 
 /**
  * An API to customize the URL behavior and retrieve URL configuration
diff --git a/src/url/urlMatcher.ts b/src/url/urlMatcher.ts
index 599cccbd..e283534a 100644
--- a/src/url/urlMatcher.ts
+++ b/src/url/urlMatcher.ts
@@ -1,14 +1,14 @@
-import { map, inherit, identity, unnest, tail, find, Obj, allTrueR, unnestR, arrayTuples } from '../common/common';
-import { prop, propEq } from '../common/hof';
-import { isArray, isString, isDefined } from '../common/predicates';
-import { Param, DefType } from '../params/param';
-import { ParamTypes } from '../params/paramTypes';
-import { RawParams } from '../params/interface';
-import { UrlMatcherCompileConfig } from './interface';
-import { joinNeighborsR, splitOnDelim } from '../common/strings';
-import { ParamType } from '../params';
-import { defaults } from '../common';
-import { ParamFactory } from './urlMatcherFactory';
+import { map, inherit, identity, unnest, tail, find, Obj, allTrueR, unnestR, arrayTuples } from '../common/common.js';
+import { prop, propEq } from '../common/hof.js';
+import { isArray, isString, isDefined } from '../common/predicates.js';
+import { Param, DefType } from '../params/param.js';
+import { ParamTypes } from '../params/paramTypes.js';
+import { RawParams } from '../params/interface.js';
+import { UrlMatcherCompileConfig } from './interface.js';
+import { joinNeighborsR, splitOnDelim } from '../common/strings.js';
+import { ParamType } from '../params/index.js';
+import { defaults } from '../common/index.js';
+import { ParamFactory } from './urlMatcherFactory.js';
 
 function quoteRegExp(str: any, param?: any) {
   let surroundPattern = ['', ''],
@@ -240,7 +240,8 @@ export class UrlMatcher {
     //    \\.                            - a backslash escape
     //    \{(?:[^{}\\]+|\\.)*\}          - a matched set of curly braces containing other atoms
     const placeholder = /([:*])([\w\[\]]+)|\{([\w\[\]]+)(?:\:\s*((?:[^{}\\]+|\\.|\{(?:[^{}\\]+|\\.)*\})+))?\}/g;
-    const searchPlaceholder = /([:]?)([\w\[\].-]+)|\{([\w\[\].-]+)(?:\:\s*((?:[^{}\\]+|\\.|\{(?:[^{}\\]+|\\.)*\})+))?\}/g;
+    const searchPlaceholder =
+      /([:]?)([\w\[\].-]+)|\{([\w\[\].-]+)(?:\:\s*((?:[^{}\\]+|\\.|\{(?:[^{}\\]+|\\.)*\})+))?\}/g;
     const patterns: any[][] = [];
     let last = 0;
     let matchArray: RegExpExecArray;
diff --git a/src/url/urlMatcherFactory.ts b/src/url/urlMatcherFactory.ts
index 66a10427..380c23dd 100644
--- a/src/url/urlMatcherFactory.ts
+++ b/src/url/urlMatcherFactory.ts
@@ -1,9 +1,9 @@
-import { extend, forEach, isDefined, isFunction, isObject } from '../common';
-import { UrlMatcher } from './urlMatcher';
-import { DefType, Param, ParamType, ParamTypeDefinition } from '../params';
-import { UrlMatcherCompileConfig } from './interface';
-import { StateDeclaration } from '../state';
-import { UIRouter } from '../router';
+import { extend, forEach, isDefined, isFunction, isObject } from '../common/index.js';
+import { UrlMatcher } from './urlMatcher.js';
+import { DefType, Param, ParamType, ParamTypeDefinition } from '../params/index.js';
+import { UrlMatcherCompileConfig } from './interface.js';
+import { StateDeclaration } from '../state/index.js';
+import { UIRouter } from '../router.js';
 
 export class ParamFactory {
   fromConfig(id: string, type: ParamType, state: StateDeclaration) {
diff --git a/src/url/urlRouter.ts b/src/url/urlRouter.ts
index ab3ca2d4..0e594f6e 100644
--- a/src/url/urlRouter.ts
+++ b/src/url/urlRouter.ts
@@ -1,10 +1,10 @@
-import { stripLastPathElement } from '../common';
-import { UrlMatcher } from './urlMatcher';
-import { RawParams } from '../params';
-import { UIRouter } from '../router';
-import { UrlRuleFactory } from './urlRule';
-import { MatchResult, UrlParts, UrlRule, UrlRuleHandlerFn } from './interface';
-import { TargetState, TargetStateDef } from '../state';
+import { stripLastPathElement } from '../common/index.js';
+import { UrlMatcher } from './urlMatcher.js';
+import { RawParams } from '../params/index.js';
+import { UIRouter } from '../router.js';
+import { UrlRuleFactory } from './urlRule.js';
+import { MatchResult, UrlParts, UrlRule, UrlRuleHandlerFn } from './interface.js';
+import { TargetState, TargetStateDef } from '../state/index.js';
 
 function appendBasePath(url: string, isHtml5: boolean, absolute: boolean, baseHref: string): string {
   if (baseHref === '/') return url;
diff --git a/src/url/urlRule.ts b/src/url/urlRule.ts
index 952cc9e3..3c4501af 100644
--- a/src/url/urlRule.ts
+++ b/src/url/urlRule.ts
@@ -1,11 +1,11 @@
-import { StateDeclaration } from '../state';
-import { UrlMatcher } from './urlMatcher';
-import { isString, isDefined, isFunction } from '../common/predicates';
-import { UIRouter } from '../router';
-import { identity, extend } from '../common/common';
-import { is, or, pattern } from '../common/hof';
-import { StateObject } from '../state/stateObject';
-import { RawParams } from '../params/interface';
+import { StateDeclaration } from '../state/index.js';
+import { UrlMatcher } from './urlMatcher.js';
+import { isString, isDefined, isFunction } from '../common/predicates.js';
+import { UIRouter } from '../router.js';
+import { identity, extend } from '../common/common.js';
+import { is, or, pattern } from '../common/hof.js';
+import { StateObject } from '../state/stateObject.js';
+import { RawParams } from '../params/interface.js';
 import {
   UrlRule,
   UrlRuleMatchFn,
diff --git a/src/url/urlRules.ts b/src/url/urlRules.ts
index 3e1e9869..f1857b25 100644
--- a/src/url/urlRules.ts
+++ b/src/url/urlRules.ts
@@ -1,10 +1,10 @@
-import { UIRouter } from '../router';
-import { Disposable } from '../interface';
-import { MatcherUrlRule, UrlRule, UrlRuleHandlerFn, UrlRuleMatchFn, UrlRulesApi } from './interface';
-import { TargetState, TargetStateDef } from '../state';
-import { UrlMatcher } from './urlMatcher';
-import { is, isDefined, isFunction, isString, removeFrom, val } from '../common';
-import { UrlRuleFactory } from './urlRule';
+import { UIRouter } from '../router.js';
+import { Disposable } from '../interface.js';
+import { MatcherUrlRule, UrlRule, UrlRuleHandlerFn, UrlRuleMatchFn, UrlRulesApi } from './interface.js';
+import { TargetState, TargetStateDef } from '../state/index.js';
+import { UrlMatcher } from './urlMatcher.js';
+import { is, isDefined, isFunction, isString, removeFrom, val } from '../common/index.js';
+import { UrlRuleFactory } from './urlRule.js';
 
 const prioritySort = (a: UrlRule, b: UrlRule) => (b.priority || 0) - (a.priority || 0);
 
diff --git a/src/url/urlService.ts b/src/url/urlService.ts
index 3652d460..25ffb59c 100644
--- a/src/url/urlService.ts
+++ b/src/url/urlService.ts
@@ -1,9 +1,9 @@
-import { UIRouter } from '../router';
-import { extend, is, isString, LocationServices, pattern } from '../common';
-import { MatchResult, UrlParts, UrlRule, UrlSyncApi } from './interface';
-import { UrlRules } from './urlRules';
-import { UrlConfig } from './urlConfig';
-import { TargetState, TargetStateDef } from '../state';
+import { UIRouter } from '../router.js';
+import { extend, is, isString, LocationServices, pattern } from '../common/index.js';
+import { MatchResult, UrlParts, UrlRule, UrlSyncApi } from './interface.js';
+import { UrlRules } from './urlRules.js';
+import { UrlConfig } from './urlConfig.js';
+import { TargetState, TargetStateDef } from '../state/index.js';
 
 /**
  * API for URL management
diff --git a/src/vanilla.ts b/src/vanilla.ts
index 3bf9d251..b7fc57c4 100644
--- a/src/vanilla.ts
+++ b/src/vanilla.ts
@@ -1 +1 @@
-export * from './vanilla/index';
+export * from './vanilla/index.js';
diff --git a/src/vanilla/baseLocationService.ts b/src/vanilla/baseLocationService.ts
index 9086791e..0349617b 100644
--- a/src/vanilla/baseLocationService.ts
+++ b/src/vanilla/baseLocationService.ts
@@ -1,8 +1,8 @@
-import { deregAll, isDefined, LocationServices, removeFrom, root } from '../common';
-import { Disposable } from '../interface';
-import { UIRouter } from '../router';
-import { HistoryLike, LocationLike } from './interface';
-import { buildUrl, getParams, parseUrl } from './utils';
+import { deregAll, isDefined, LocationServices, removeFrom, root } from '../common/index.js';
+import { Disposable } from '../interface.js';
+import { UIRouter } from '../router.js';
+import { HistoryLike, LocationLike } from './interface.js';
+import { buildUrl, getParams, parseUrl } from './utils.js';
 
 /** A base `LocationServices` */
 export abstract class BaseLocationServices implements LocationServices, Disposable {
diff --git a/src/vanilla/browserLocationConfig.ts b/src/vanilla/browserLocationConfig.ts
index 945fb4de..76d2f35f 100644
--- a/src/vanilla/browserLocationConfig.ts
+++ b/src/vanilla/browserLocationConfig.ts
@@ -1,5 +1,5 @@
-import { isDefined, isUndefined } from '../common/predicates';
-import { LocationConfig } from '../common/coreservices';
+import { isDefined, isUndefined } from '../common/predicates.js';
+import { LocationConfig } from '../common/coreservices.js';
 
 /** A `LocationConfig` that delegates to the browser's `location` object */
 export class BrowserLocationConfig implements LocationConfig {
diff --git a/src/vanilla/hashLocationService.ts b/src/vanilla/hashLocationService.ts
index afa6ee49..75088cc0 100644
--- a/src/vanilla/hashLocationService.ts
+++ b/src/vanilla/hashLocationService.ts
@@ -1,6 +1,6 @@
-import { root, trimHashVal } from '../common';
-import { UIRouter } from '../router';
-import { BaseLocationServices } from './baseLocationService';
+import { root, trimHashVal } from '../common/index.js';
+import { UIRouter } from '../router.js';
+import { BaseLocationServices } from './baseLocationService.js';
 
 /** A `LocationServices` that uses the browser hash "#" to get/set the current location */
 export class HashLocationService extends BaseLocationServices {
diff --git a/src/vanilla/index.ts b/src/vanilla/index.ts
index 682ae6de..19696d47 100644
--- a/src/vanilla/index.ts
+++ b/src/vanilla/index.ts
@@ -3,18 +3,18 @@
  *
  * @packageDocumentation
  */
-export * from './interface';
+export * from './interface.js';
 
-export * from './q';
-export * from './injector';
+export * from './q.js';
+export * from './injector.js';
 
-export * from './baseLocationService';
-export * from './hashLocationService';
-export * from './memoryLocationService';
-export * from './pushStateLocationService';
+export * from './baseLocationService.js';
+export * from './hashLocationService.js';
+export * from './memoryLocationService.js';
+export * from './pushStateLocationService.js';
 
-export * from './memoryLocationConfig';
-export * from './browserLocationConfig';
+export * from './memoryLocationConfig.js';
+export * from './browserLocationConfig.js';
 
-export * from './utils';
-export * from './plugins';
+export * from './utils.js';
+export * from './plugins.js';
diff --git a/src/vanilla/injector.ts b/src/vanilla/injector.ts
index cb9a5cf6..58cfa6e1 100644
--- a/src/vanilla/injector.ts
+++ b/src/vanilla/injector.ts
@@ -6,7 +6,7 @@ import {
   isInjectable,
   $InjectorLike,
   IInjectable,
-} from '../common/index';
+} from '../common/index.js';
 
 // globally available injectables
 const globals = {};
diff --git a/src/vanilla/interface.ts b/src/vanilla/interface.ts
index 8ca3cab7..21f32a19 100644
--- a/src/vanilla/interface.ts
+++ b/src/vanilla/interface.ts
@@ -1,6 +1,6 @@
-import { LocationConfig, LocationServices } from '../common/coreservices';
-import { UIRouterPlugin } from '../interface';
-import { $InjectorLike, $QLike } from '../common/index';
+import { LocationConfig, LocationServices } from '../common/coreservices.js';
+import { UIRouterPlugin } from '../interface.js';
+import { $InjectorLike, $QLike } from '../common/index.js';
 
 export interface LocationPlugin extends UIRouterPlugin {
   service: LocationServices;
diff --git a/src/vanilla/memoryLocationConfig.ts b/src/vanilla/memoryLocationConfig.ts
index 17c381a0..7ffec04a 100644
--- a/src/vanilla/memoryLocationConfig.ts
+++ b/src/vanilla/memoryLocationConfig.ts
@@ -1,6 +1,6 @@
-import { LocationConfig } from '../common/coreservices';
-import { isDefined } from '../common/predicates';
-import { noop } from '../common/common';
+import { LocationConfig } from '../common/coreservices.js';
+import { isDefined } from '../common/predicates.js';
+import { noop } from '../common/common.js';
 
 /** A `LocationConfig` mock that gets/sets all config from an in-memory object */
 export class MemoryLocationConfig implements LocationConfig {
diff --git a/src/vanilla/memoryLocationService.ts b/src/vanilla/memoryLocationService.ts
index 83d63d6c..db461109 100644
--- a/src/vanilla/memoryLocationService.ts
+++ b/src/vanilla/memoryLocationService.ts
@@ -1,5 +1,5 @@
-import { BaseLocationServices } from './baseLocationService';
-import { UIRouter } from '../router';
+import { BaseLocationServices } from './baseLocationService.js';
+import { UIRouter } from '../router.js';
 
 /** A `LocationServices` that gets/sets the current location from an in-memory object */
 export class MemoryLocationService extends BaseLocationServices {
diff --git a/src/vanilla/plugins.ts b/src/vanilla/plugins.ts
index 3b9f9680..de7eef1f 100644
--- a/src/vanilla/plugins.ts
+++ b/src/vanilla/plugins.ts
@@ -1,14 +1,14 @@
-import { BrowserLocationConfig } from './browserLocationConfig';
-import { HashLocationService } from './hashLocationService';
-import { locationPluginFactory } from './utils';
-import { LocationPlugin, ServicesPlugin } from './interface';
-import { UIRouter } from '../router';
-import { PushStateLocationService } from './pushStateLocationService';
-import { MemoryLocationService } from './memoryLocationService';
-import { MemoryLocationConfig } from './memoryLocationConfig';
-import { $injector } from './injector';
-import { $q } from './q';
-import { services } from '../common/coreservices';
+import { BrowserLocationConfig } from './browserLocationConfig.js';
+import { HashLocationService } from './hashLocationService.js';
+import { locationPluginFactory } from './utils.js';
+import { LocationPlugin, ServicesPlugin } from './interface.js';
+import { UIRouter } from '../router.js';
+import { PushStateLocationService } from './pushStateLocationService.js';
+import { MemoryLocationService } from './memoryLocationService.js';
+import { MemoryLocationConfig } from './memoryLocationConfig.js';
+import { $injector } from './injector.js';
+import { $q } from './q.js';
+import { services } from '../common/coreservices.js';
 
 export function servicesPlugin(router: UIRouter): ServicesPlugin {
   services.$injector = $injector;
diff --git a/src/vanilla/pushStateLocationService.ts b/src/vanilla/pushStateLocationService.ts
index ff30695d..f05bd4f2 100644
--- a/src/vanilla/pushStateLocationService.ts
+++ b/src/vanilla/pushStateLocationService.ts
@@ -1,6 +1,6 @@
-import { UIRouter } from '../router';
-import { BaseLocationServices } from './baseLocationService';
-import { LocationConfig, root, splitHash, splitQuery, stripLastPathElement } from '../common';
+import { UIRouter } from '../router.js';
+import { BaseLocationServices } from './baseLocationService.js';
+import { LocationConfig, root, splitHash, splitQuery, stripLastPathElement } from '../common/index.js';
 
 /**
  * A `LocationServices` that gets/sets the current location using the browser's `location` and `history` apis
diff --git a/src/vanilla/q.ts b/src/vanilla/q.ts
index 43555f8e..579f7727 100644
--- a/src/vanilla/q.ts
+++ b/src/vanilla/q.ts
@@ -1,4 +1,4 @@
-import { isArray, isObject, $QLike } from '../common/index';
+import { isArray, isObject, $QLike } from '../common/index.js';
 
 /**
  * An angular1-like promise api
diff --git a/src/vanilla/utils.ts b/src/vanilla/utils.ts
index 046623f5..19f90234 100644
--- a/src/vanilla/utils.ts
+++ b/src/vanilla/utils.ts
@@ -7,8 +7,8 @@ import {
   splitEqual,
   splitHash,
   splitQuery,
-} from '../common';
-import { UIRouter } from '../router';
+} from '../common/index.js';
+import { UIRouter } from '../router.js';
 
 export const keyValsToObjectR = (accum, [key, val]) => {
   if (!accum.hasOwnProperty(key)) {
diff --git a/src/view/index.ts b/src/view/index.ts
index b7c8b4de..5afeeea4 100644
--- a/src/view/index.ts
+++ b/src/view/index.ts
@@ -1,2 +1,2 @@
-export * from './interface';
-export * from './view';
+export * from './interface.js';
+export * from './view.js';
diff --git a/src/view/interface.ts b/src/view/interface.ts
index 93281c5c..637830b7 100644
--- a/src/view/interface.ts
+++ b/src/view/interface.ts
@@ -1,5 +1,5 @@
-import { _ViewDeclaration } from '../state/interface';
-import { PathNode } from '../path/pathNode';
+import { _ViewDeclaration } from '../state/interface.js';
+import { PathNode } from '../path/pathNode.js';
 
 /** The context ref can be anything that has a `name` and a `parent` reference to another IContextRef */
 export interface ViewContext {
diff --git a/src/view/view.ts b/src/view/view.ts
index f0ac0885..27e5bf47 100644
--- a/src/view/view.ts
+++ b/src/view/view.ts
@@ -1,11 +1,11 @@
-import { equals, applyPairs, removeFrom, TypedMap, inArray, find } from '../common/common';
-import { curry, prop } from '../common/hof';
-import { isString, isArray } from '../common/predicates';
-import { trace } from '../common/trace';
-import { PathNode } from '../path/pathNode';
-import { ActiveUIView, ViewContext, ViewConfig } from './interface';
-import { _ViewDeclaration } from '../state/interface';
-import { UIRouter } from '../router';
+import { equals, applyPairs, removeFrom, TypedMap, inArray, find } from '../common/common.js';
+import { curry, prop } from '../common/hof.js';
+import { isString, isArray } from '../common/predicates.js';
+import { trace } from '../common/trace.js';
+import { PathNode } from '../path/pathNode.js';
+import { ActiveUIView, ViewContext, ViewConfig } from './interface.js';
+import { _ViewDeclaration } from '../state/interface.js';
+import { UIRouter } from '../router.js';
 
 export type ViewConfigFactory = (path: PathNode[], decl: _ViewDeclaration) => ViewConfig | ViewConfig[];