Lazy loading in Angular2 RC7 and angular-cli webpack

[stephenwilson1984]

Please provide us with the following information:

1. OS? Windows 7, 8 or 10. Linux (which distribution). Mac OSX (Yosemite? El Capitan?)
   Windows 7

2. Versions. Please run ng --version. If there's nothing outputted, please run
   in a Terminal: node --version and paste the result here:
   angular-cli: 1.0.0-beta.11-webpack.9-4
   node: 6.5.0
   os: win32 x64

3. Repro steps. Was this an app that wasn't created using the CLI? What change did you
   do on your code? etc.
   Created a boilerplate app using "ng new" then added a basic home module manually.

4. The log given by the failure. Normally this include a stack trace and some
   more information.
   error_handler.js:45EXCEPTION: Uncaught (in promise): Error: Cannot find module '/app/home.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:196Zone.runGuarded @ zone.js:102_loop_1 @ zone.js:368drainMicroTaskQueue @ zone.js:375
   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:196Zone.runGuarded @ zone.js:102_loop_1 @ zone.js:368drainMicroTaskQueue @ zone.js:375
   error_handler.js:51Error: Uncaught (in promise): Error: Cannot find module '/app/home.module'.
   at resolvePromise (zone.js:418)
   at zone.js:395
   at ZoneDelegate.invoke (zone.js:192)
   at Object.onInvoke (ng_zone_impl.js:43)
   at ZoneDelegate.invoke (zone.js:191)
   at Zone.run (zone.js:85)
   at zone.js:451
   at ZoneDelegate.invokeTask (zone.js:225)
   at Object.onInvokeTask (ng_zone_impl.js:34)
   at ZoneDelegate.invokeTask (zone.js:224)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:196Zone.runGuarded @ zone.js:102_loop_1 @ zone.js:368drainMicroTaskQueue @ zone.js:375
   zone.js:344Unhandled Promise rejection: Cannot find module '/app/home.module'. ; Zone: angular ; Task: Promise.then ; Value: Error: Cannot find module '/app/home.module'.(…) Error: Cannot find module '/app/home.module'.
   at webpackEmptyContext (http://localhost:4200/main.bundle.js:41545:8)
   at SystemJsNgModuleLoader.loadAndCompile (http://localhost:4200/main.bundle.js:50064:40)
   at SystemJsNgModuleLoader.load (http://localhost:4200/main.bundle.js:50057:60)
   at RouterConfigLoader.loadModuleFactory (http://localhost:4200/main.bundle.js:16894:128)
   at RouterConfigLoader.load (http://localhost:4200/main.bundle.js:16886:81)
   at MergeMapSubscriber.project (http://localhost:4200/main.bundle.js:52671:111)
   at MergeMapSubscriber._tryNext (http://localhost:4200/main.bundle.js:25798:27)
   at MergeMapSubscriber._next (http://localhost:4200/main.bundle.js:25788:18)
   at MergeMapSubscriber.Subscriber.next (http://localhost:4200/main.bundle.js:5728:18)
   at ScalarObservable._subscribe (http://localhost:4200/main.bundle.js:40540:24)consoleError @ zone.js:344_loop_1 @ zone.js:371drainMicroTaskQueue @ zone.js:375
   zone.js:346Error: Uncaught (in promise): Error: Cannot find module '/app/home.module'.(…)

5. Mention any other details that might be useful.
   Also a question raised on StackOverflow with more details: http://stackoverflow.com/q/39493782/616304

   ---

   Thanks! We'll be in touch soon.

[slubowsky]

Try killing and restarting ng serve. Worked for me, see #2033

[mjolk]

yep it works, gj!

[ritz078]

@slubowsky @mjolk is there any way i can change the name of generated chunks that you know ? my chunks are named 0.chunk.js, 1.chunk.js and so on.

[mjolk]

@ritz078 normally this is easy to do in webpack config but in this case this config is entirely managed by angular-cli... if needs must you could edit https://github.com/angular/angular-cli/blob/4c4e31d44c7b17078ebac6f4689db11c47285661/packages/angular-cli/models/webpack-build-development.ts#L10 and https://github.com/angular/angular-cli/blob/4c4e31d44c7b17078ebac6f4689db11c47285661/packages/angular-cli/models/webpack-build-production.ts#L14

[ritz078]

that's definitely not a solution. will create a separate issue.

[stephenwilson1984]

Nothing has worked for me. Killing and restarting ng serve has no effect. I've seen another post exactly the same as this on stack overflow so I'm not the only one getting this. One person has suggested the below:

"The mechanism you are using is still systemjs based. I couldn't make it work with webpack using the "path#class" syntax. So we require the module directly:

First we'll need the es6-promise-loader:

npm i --save-dev es6-promise-loader

Then define your route like this:

{path:"lazy", loadChildren: () => require('es6-promise!./path/to/module')('ClassName')}"

I'm not sure about this though. I would have thought the lazy loading that used to work with System JS should work the same in webpack with no extra config. Am I wrong?

[marklagendijk]

I just got it working. Restarting ng serve worked for me.
Make sure you are using the full path, so app/my-lazy-module/my-lazy-module.module#MyLazyModule instead of ./app/my-lazy-module/my-lazy-module.module#MyLazyModule. The relative syntax does not (yet?) work.

[mxii]

Isn't it possible to lazy load just a Component instead of a whole NgModule?

[andyrue]

With the latest beta.14 and Angular 2.0.0 Final I used app/home/home.module without specifying the module class to load with #HomeModule.

[chosroes]

Maybe it's better to follow the documentation style:
https://angular.io/docs/ts/latest/guide/router.html

const adminRoutes: Routes = [ { path: 'admin', loadChildren: 'app/admin/admin.module#AdminModule', } ];

[andyrue]

@chosroes That's how I was originally doing it but it could never find the module file. Removing the #HomeModule part got it working. Confusing!

[reflog]

One thing that failed me at first: make sure that the class inside your module is NOT exported as 'default', otherwise it will not be picked up by systemJS loader!

[andyrue]

@reflog Thanks for pointing that out. After removing default from my exported class I was then able to use app/home/home.module#HomeModule method. Seems that's the documented way to do things now. But note that the other way appears to work as well if you export default and don't specify the module class in the path.

[chosroes]

@andyrue Yeah, default means that you have not to specify the module.

[PostImpatica]

Are you guys seeing it actually create additional bundles? Cuz although this appears to be working, in that I'm not getting any errors, it doesn't appear to be creating separate bundles. Therefore, nothing is really being lazy loaded when you look at the network tab.

UPDATE: Never mind, I had to remove the module from the main app.module.ts and now it loads as a seperate chunk. I was surprised this worked, lol.

[davidejones]

I'm having the same issue mostly because the children aren't relative to the the project. I have it in another package. Is there anyway to have loadChildren work like import somehow?

import { CoreModule } from '@blahblah/core-stuff';

[ritz078]

Lazy loading Worked for me
https://twitter.com/ritz078/status/777057390487146497
On Wed, 21 Sep 2016 at 2:34 AM, David Jones [email protected]
wrote:

I'm having the same issue mostly because the children aren't relative to
the the project. I have it in another package. Is there anyway to have
loadChildren work like import somehow?

import { CoreModule } from '@blahblah/core-stuff';

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Reply to this email directly, view it on GitHub
#2112 (comment),
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.

[scrivy]

does anybody have a working plnkr example? I'm using angular-cli and can't figure it out

[tianyangj]

Lazy loading seems to be working for me.

I created a simple repo with two modules, one eager loaded and one lazy loaded, https://github.com/tianyangj/angular-cli.

[filipesilva]

@stephenwilson1984 are you still having problems? If you show me repo with the latest CLI, I can try to debug.

[stephenwilson1984]

Hi, Everything is fine now, we ditched angular-cli and stayed using SystemJs which works fine for now.

Thanks,
Stephen

[deebloo]

@filipesilva would using the same module in the root app and a lazy loaded module cause this? For example. I have a core module. In the root app I call forRoot to configure a provider. Then when I import that same module in a lazy loaded module I do not get multiple bundles

[deebloo]

@filipesilva I think the issue is that it is not obvious how the cli decides to create bundles since it seems it is not just defined by defining a module to be lazy loaded.

[Delagen]

Load children in webpack try to use SystemJS loader for resolve. But I don't want to use it.
Angular 2 template Loader works fine. Why AOT generation from ngtools/webpack produce it?
Direct use of NGC (ngc -p) produces valid ngfactory.

[Delagen]

@tianyangj
ng build --prod --aot

 10% building modules 6/7 modules 1 active ...\index.js!C:\1\new-ng-app\src\main.tsError: AboutModule is not an NgModule

    at NgcWebpackPlugin.getNgModuleMetadata (C:\1\new-ng-app\node_modules\@ngtools\webpack\src\plugin.js:121:19)
    at NgcWebpackPlugin._processNgModule (C:\1\new-ng-app\node_modules\@ngtools\webpack\src\plugin.js:109:42)
    at C:\1\new-ng-app\node_modules\@ngtools\webpack\src\plugin.js:114:34
    at Array.reduce (native)
    at NgcWebpackPlugin._processNgModule (C:\1\new-ng-app\node_modules\@ngtools\webpack\src\plugin.js:111:29)
    at C:\1\new-ng-app\node_modules\@ngtools\webpack\src\plugin.js:96:37
 10% building modules 7/7 modules 0 active

but ng build --prod works

[pleerock]

I have same issue here. using webpack without angular cli worked fine, but with cli it does not generate bundles

[onedotover]

I was having the same issue as @Delagen. I was defining routes in this format from https://angular.io/docs/ts/latest/guide/router.html.

const routes: Routes = [
  {path: "", component: HomeComponent},
  {path: "lazy", loadChildren: "app/lazy-test/lazy.module#LazyModule"}
];
export const AppRoutes = RouterModule.forRoot(routes);

ng build --aot >> LazyModule is not an NgModule

Updating to the module format used in the angular-cli blueprints works fixes this error

const routes: Routes = [
  {path: "", component: HomeComponent},
  {path: "lazy", loadChildren: "app/lazy-test/lazy.module#LazyModule"}
];

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

Once you get past this issue you hit #2452 noted above.

[Delagen]

@onedotover No I issue different problem

[aaronleestic]

@filipesilva I encountered a lazy loading issue but it is unlike stephenwilson1984's. Instead of 'Cannot find module', the main bundle includes the lazily loaded module.

Per your request I have a repo that reproduces the issue, under this related issue:
#2496 (comment)

[pleerock]

same for me, everything is packed into single module, instead having multiple generated bundles.

[Delagen]

angular-cli beta 17 the same issue.
Even bundle broken due ngtools/webpack@latest resolved to 1.0.0 but needed 1.1.0 with only tagged as experimental. No testing at all. Sad (((

[filipesilva]

For issues related to AOT and lazy loaded modules, please use #2452 instead of this issue.

We have a custom mechanism in the CLI to find and separately bundle lazy loaded routes that does not need SystemJS and instead uses Webpack2.

Regarding bundles not being generated. the cause is likely that you are importing that module elsewhere in the app, as mentioned in #2112 (comment).

As long as there is at least one ES6 import statement in your code that requires that file it will never be factored out into a lazy loaded module. That makes sense though... if you have an import then it can't be lazily loaded, there's a part of your app that needs it right then and now.

I'm closing this issue because the exact reported issue doesn't exist anymore, it was originally for an older version, the original poster isn't part of the discussion anymore, and the thread is branching out to related but different issues.

Please open new issues for problems you're still having with lazy loaded modules.

[danya0365]

I'm using angular-cli "version": "1.0.0-beta.16"

with first time I have config for lazy load

loadChildren: 'app/my-account/my-account.module#MyAccountModule'

it's not worked.

I try to close web server then run ng-serve again it's worked again

web pack has been generate 0.chunk.js & 0.map file

[kentoj]

I confirm that the restarting of ng serve fixed the problem for me. I saw the additional chunk being generated in the network tab. I had to make sure as others have said that there were no imports in app.module.ts or app-routing.module.ts to the module the app was supposed to lazy load. It would be nice to mention this in the docs since it is probably an easy beginner mistake, especially since the () => ModuleName syntax exists out there. I saw that on a blog post and on another issue on this repo. After much searching I came across this issue, which solved the issue entirely for me.

[thucnguyen77]

"restarting ng serve" worked for me too

[pleerock]

still not working for me... How does cli "automatically understand and find lazy routes"? Maybe I do something wrong that this automatic code cant find any matches in my project? I have AppRoutes file that contains such code:

export const APP_ROUTES: Routes = [
    {
        path: "posts",
        loadChildren: "../modules/content-modules/post/PostModule#PostModule"
    },
];

[da45]

make sure that you included 'Routes' in the lazy module as described below:
import { Routes, RouterModule } from '@angular/router';

[dustintheweb]

Felt this bug for the first time today. No issues locally (dev or production / Mac OS), but got hit with it after I pushed to my production server (Heroku / Ubuntu).
Here's how I fixed it: http://stackoverflow.com/a/41780310/923454

[guilhermelucio]

I just put the route in the app.module.ts file, if I add a new file called route.module.ts and try to import within the app.module.ts file, the app will crash, so if you just leave the code inline, it should work.

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

const routes: Routes = [
  { path: '',  loadChildren: './home/home.module#HomeModule' },
  { path: 'contacts', component: ContactsComponent }
];

const routerModule = RouterModule.forRoot(routes);

@NgModule({
  declarations: [
    AppComponent,
    ContactsComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpModule,
    routerModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})

References:
https://github.com/mauricedb/lazy-routes.git

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