CODEWITHSUNDEEP
angularmodulelazy-loading
arthurr
arthurr

Reputation: 1145

Angular2 lazy loading module error 'cannot find module'

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

Upvotes: 62

Views: 84823

Answers (16)

asgarov1
asgarov1

Reputation: 4171

in my project i resolved the issue by changing the relative path to start from src

so instead of

loadChildren: () => import('./user/user.module') .then(m => m.UserModule)

I changed to:

loadChildren: () => import('./src/app/user/user.module') .then(m => m.UserModule)

Folder structure was: enter image description here

Upvotes: 0

Alexei - check Codidact
Alexei - check Codidact

Reputation: 23098

For newer Angular versions (10+?) lazy loading is done using the following syntax:

{ path: "foos", loadChildren: () => import ("./foos/foo.module").then(m => m.FooModule) },

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 }
];

Also check this issue (thanks to rey_coder).

Upvotes: 42

Zohab Ali
Zohab Ali

Reputation: 9584

In Angular 9 I did this and it worked for me: loadChildren: () => import('./items/items.module').then(m => m.ItemsModule)

You can have a look on official documentation

Upvotes: 4

YellowStrawHatter
YellowStrawHatter

Reputation: 948

For people who are using a recent Angular version (v9 in my case), you can setup your route with the following syntax declaration: 

import { TestModule } from './modules/test.module';
const appRoutes: Routes = [
  { path: 'blogs', loadChildren: () => import('./modules/test.module').then(m => m.TestModule) },
];

// NgModule
// declarations
// imports
// providers
// bootstrap

export class AppModule { }

Another way (without making the import at the top):

    const appRoutes: Routes = [
      { path: 'blogs', loadChildren: () => import('./modules/test.module').then(m => m.TestModule) },
    ];

Upvotes: 19

Ray_Hack
Ray_Hack

Reputation: 981

In my case the path shared the same route as one I declared elsewhere, assuming they would be relative paths. e.g like below in the

Not Working

Admin Module

    {
    path: 'organisation',
    canActivate: [AuthGuard],
      loadChildren: './organisation/organisation.module#AdminOrganisationModule',
    },

User Module

    {
    path: 'organisation',
    canActivate: [AuthGuard],
      loadChildren: './organisation/organisation.module#UserOrganisationModule',
    },

individually, when only one was declared, these were working fine, but not together as it complained about the ./organisation/organisation.module path , I changed both to the pattern below and it was ok.

Working

Admin Module

    {
    path: 'organisation',
    canActivate: [AuthGuard],
      loadChildren: '../admin/organisation/organisation.module#AdminOrganisationModule',
    },

User Module

        {
    path: 'organisation',
    canActivate: [AuthGuard],
      loadChildren: '../user/organisation/organisation.module#UserOrganisationModule',
    },

Upvotes: 1

alaboudi
alaboudi

Reputation: 3423

I have solved my own issue. Don't put the .ts in the path name. Rather than using 'path/to/my/module.ts#MyModuleClass', use 'path/to/my/module#MyModuleClass'

Upvotes: 1

Ankita P.
Ankita P.

Reputation: 478

I had a similar issue. I just restarted the server and it worked. :)

Upvotes: 1

Runny Yolk
Runny Yolk

Reputation: 1164

I've been troubleshooting this for a a couple of hours on a project I've just taken over from. None of the above solutions were working, but then I realised that all the lazy-loaded modules had the .ts extension.

If anyone else is having issues, check if you need to change loadChildren: 'app/example.module.ts' to loadChildren: 'app/example.module'.

Upvotes: 2

Roney Francis
Roney Francis

Reputation: 365

It was worked for me by using.

../app/

I solved this issue by using the suggestion popup in VS code. You can also follow that. No need to go anywhere. (I Think, the path may vary in every project.)

Upvotes: 3

Officialzessu
Officialzessu

Reputation: 984

You need to change

export default class TestModule { }

to

export class TestModule { }

That should fix your problems

Upvotes: 0

Ruby Junior Dev
Ruby Junior Dev

Reputation: 118

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.

Upvotes: 3

Jasnan
Jasnan

Reputation: 4514

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.

Upvotes: 34

da45
da45

Reputation: 381

make sure to include import { Routes, RouterModule } from '@angular/router'; in the module to load lazely

Upvotes: 1

Pageii Studio
Pageii Studio

Reputation: 2096

In a use-case scenario to segregate a distinct feature (e.g. test.module.ts) from its root application (i.e. app.module.ts) through a lazily-loaded module, we could create the test module and it's components in a sub-folder (e.g. src/app/test/). The test-routing.module could be configured this way:

//test-routing.module.ts
//routes to test.component.ts as an example

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

const feature_test_routes: Routes = [

    { 
        path: '',
        component: TestComponent
    }

];

export const TestRoutingModule = RouterModule.forChild(feature_test_routes);

The "parent" module (app-routing.module.ts), would have a route that looks like this:

//app-routing.module.ts
//routes to http://localhost:4200/test

import { Routes, RouterModule } from '@angular/router';
import { AppComponent } from './app.component';
const root_routes: Routes = [

    { 
        path: '',
        component: AppComponent, 
        children: [
            {
                path: 'test',
                loadChildren: './test/test.module#TestModule'
            }
        ]
    }

];

export const AppRoutingModule = RouterModule.forChild(root_routes);

This allows the root application and entry component, imperatively loaded, to subsequently lazy-load features from test.module.ts as a child when needed.

Upvotes: 1

James Salamon
James Salamon

Reputation: 1422

restarting ng serve worked for me

Upvotes: 71

arthurr
arthurr

Reputation: 1145

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.

Upvotes: 12

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