Angular2 lazy loading module error 'cannot fin

Question

I was trying to find any solution for this error but nothing works for me. I have simple Angular2 App created with Angular-CLI. When I serve this app in browser I'm getting this error: EXCEPTION: Uncaught (in promise): Error: Cannot find module '/app/test.module'. I was trying using different path in loadChildren:

'/app/test.module'
'./app/test.module'
'./test.module'
'/src/app/test.module'

Folders

src/
  app/
    app-routing.module.ts
    app.component.ts
    app.module.ts
    test.component.ts
    test.module.ts

app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { HttpModule } from '@angular/http';

import { RoutingModule } from './app-routing.module';

import { AppComponent } from './app.component';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule,
    RoutingModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

app-routing.module.ts

import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';


const routes: Routes = [
  { path: '', loadChildren: '/app/test.module' }
];

@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule],
  providers: []
})
export class RoutingModule { }

test.module.ts

import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';
import { CommonModule } from '@angular/common';
import { TestComponent } from './test.component';

export const routes: Routes = [
  { path: '', component: TestComponent }
];

@NgModule({
  imports: [
    CommonModule,
    RouterModule.forChild(routes)
  ],
  exports: [TestComponent],
  declarations: [TestComponent]
})
export default class TestModule { }

stack trace

    error_handler.js:45EXCEPTION: Uncaught (in promise): Error: Cannot find module '/app/test.module'.ErrorHandler.handleError @ error_handler.js:45next @ application_ref.js:273schedulerFn @ async.js:82SafeSubscriber.__tryOrUnsub @ Subscriber.js:223SafeSubscriber.next @ Subscriber.js:172Subscriber._next @ Subscriber.js:125Subscriber.next @ Subscriber.js:89Subject.next @ Subject.js:55EventEmitter.emit @ async.js:74onError @ ng_zone.js:120onHandleError @ ng_zone_impl.js:64ZoneDelegate.handleError @ zone.js:207Zone.runGuarded @ zone.js:113_loop_1 @ zone.js:379drainMicroTaskQueue @ zone.js:386
2016-10-08 14:22:50.612 error_handler.js:50ORIGINAL STACKTRACE:ErrorHandler.handleError @ error_handler.js:50next @ application_ref.js:273schedulerFn @ async.js:82SafeSubscriber.__tryOrUnsub @ Subscriber.js:223SafeSubscriber.next @ Subscriber.js:172Subscriber._next @ Subscriber.js:125Subscriber.next @ Subscriber.js:89Subject.next @ Subject.js:55EventEmitter.emit @ async.js:74onError @ ng_zone.js:120onHandleError @ ng_zone_impl.js:64ZoneDelegate.handleError @ zone.js:207Zone.runGuarded @ zone.js:113_loop_1 @ zone.js:379drainMicroTaskQueue @ zone.js:386
2016-10-08 14:22:50.613 error_handler.js:51Error: Uncaught (in promise): Error: Cannot find module '/app/test.module'.
    at resolvePromise (zone.js:429)
    at zone.js:406
    at ZoneDelegate.invoke (zone.js:203)
    at Object.onInvoke (ng_zone_impl.js:43)
    at ZoneDelegate.invoke (zone.js:202)
    at Zone.run (zone.js:96)
    at zone.js:462
    at ZoneDelegate.invokeTask (zone.js:236)
    at Object.onInvokeTask (ng_zone_impl.js:34)
    at ZoneDelegate.invokeTask (zone.js:235)ErrorHandler.handleError @ error_handler.js:51next @ application_ref.js:273schedulerFn @ async.js:82SafeSubscriber.__tryOrUnsub @ Subscriber.js:223SafeSubscriber.next @ Subscriber.js:172Subscriber._next @ Subscriber.js:125Subscriber.next @ Subscriber.js:89Subject.next @ Subject.js:55EventEmitter.emit @ async.js:74onError @ ng_zone.js:120onHandleError @ ng_zone_impl.js:64ZoneDelegate.handleError @ zone.js:207Zone.runGuarded @ zone.js:113_loop_1 @ zone.js:379drainMicroTaskQueue @ zone.js:386
2016-10-08 14:22:50.614 zone.js:355Unhandled Promise rejection: Cannot find module '/app/test.module'. ; Zone: angular ; Task: Promise.then ; Value: Error: Cannot find module '/app/test.module'.(…) Error: Cannot find module '/app/test.module'.
    at webpackEmptyContext (http://localhost:4200/main.bundle.js:49550:8)
    at SystemJsNgModuleLoader.loadAndCompile (http://localhost:4200/main.bundle.js:57952:40)
    at SystemJsNgModuleLoader.load (http://localhost:4200/main.bundle.js:57945:60)
    at RouterConfigLoader.loadModuleFactory (http://localhost:4200/main.bundle.js:22354:128)
    at RouterConfigLoader.load (http://localhost:4200/main.bundle.js:22346:81)
    at MergeMapSubscriber.project (http://localhost:4200/main.bundle.js:61105:111)
    at MergeMapSubscriber._tryNext (http://localhost:4200/main.bundle.js:32515:27)
    at MergeMapSubscriber._next (http://localhost:4200/main.bundle.js:32505:18)
    at MergeMapSubscriber.Subscriber.next (http://localhost:4200/main.bundle.js:7085:18)
    at ScalarObservable._subscribe (http://localhost:4200/main.bundle.js:48555:24)consoleError @ zone.js:355_loop_1 @ zone.js:382drainMicroTaskQueue @ zone.js:386
2016-10-08 14:22:50.620 zone.js:357Error: Uncaught (in promise): Error: Cannot find module '/app/test.module'.(…)consoleError @ zone.js:357_loop_1 @ zone.js:382drainMicroTaskQueue @ zone.js:386

Answer 1

restarting ng serve worked for me

Answer 2

I change this

{
            path: 'test',
            loadChildren: 'app/tests/test.module#TestModule'

}

for this

   {
        path: 'test', loadChildren: () => new Promise(resolve => {
            (require as any).ensure([], require => {
                resolve(require('app/tests/test.module').TestModule);
            })
        })
    },

And solved my problem.

Answer 3

I have faced this same issue. I solved it by doing following 2 things:

In root module's route configuration, use loadChildren with a relative path to the lazy loaded angular module. The string is delimited with a # where the right side of split is the lazy loaded module's class name.

I have added ./ as prefix to the loadChildren string.

{ path:'user', loadChildren:'./app/user/user.module#UserModule'}

I am using webpack 2 and it needs a loader for Angular 2 that enables string-based module loading with the Angular Router. Add this to the project

yarn add angular-router-loader -D

then add the angular-router-loader to typescript loaders

loaders: [
  {
    test: /\.ts$/,
    loaders: [
    'awesome-typescript-loader',
    'angular-router-loader'
    ]
  }
]

and its working for me.

Answer 4

Finally I found out that I need to import lazy loaded module in routing config this way:

const routes: Routes = [
   { path: '', loadChildren: 'app/test.module' }
];

without any / or ./in front of module path.

Answer 5

I met a similar issue when working with Angular 4.4.5 and webpack and managed to fix it without using strings, but module type reference (much easier to write and less error prone):

const routes: Routes = [
  { path: '', loadChildren: () => TestModule }
];

I could not find the minimum version for Angular (loader) the supports this syntax.

---

A way that might work with AOT is to replace lambda syntax with a regular one:

export function getTestModule() { return TestModule; }

const routes: Routes = [
  { path: '', loadChildren: getTestModule }
];

Answer 6

You need to change

export default class TestModule { }

to

export class TestModule { }

That should fix your problems