AoT Compiler unable to resolve module with "export default class"

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Current behavior
To allow a module to be loaded lazily, I define its route like so:

{
    path: 'report',
    loadChildren: '/app/report/report.module'
}

And I declare it as the default class in report.module.ts so the router will know what to load:

export default class ReportModule {}

Using export default class ReportModule {} instead of export class ReportModule {} when declaring modules breaks ngc. During compilation I get error:

can't resolve module C:/path/to/report.module.ts from C:/path/to/report.module.ts
Error: can't find symbol ReportModule exported from module C:/path/to/report.module.ts
    at ReflectorHost.findDeclaration (C:\path\to\@angular\compiler-cli\src\reflector_host.js:174:23)
    at _loop_1 (C:\path\to\@angular\compiler-cli\src\codegen.js:52:51)
    ...
Compilation failed

I left the orientation of the slashes (forward / and back \) as they appear in the console

Expected/desired behavior

An earlier version of the docs on ngModule suggested using export default to expose lazy-loaded modules. This works well with Just-in-Time compilation. So I expected the AoT compiler to be able to parse them as well

Reproduction of the problem

Try compiling an application with a module declared with export default

Please tell us about your environment:

Angular version: 2.0.0-rc.6
Browser: [all]
Language: [TypeScript 2]

@chuckjaz

/cc @chuckjaz

@mhevery

@mhevery @alexeagle Chuck says this is related to your module resolution changes.

@vsavkin

@vsavkin it seems like the Router does not understand default exports?

No, this is in ReflectorHost so I don't think it's router-specific.

I think the compiler / codgen pipeline in general doesn't handle default exports (yet)

feat(@ngtools/webpack): support import syntax for loadChildren with V…

This is still a thing, error message could be better:
'ERROR in : Unexpected value 'null' imported by the module' when you export a routing module as default.

If I hadn't found a thread referencing the same error this would've been a pain to solve.

Haven't checked, but I just saw commint two commits that landed into Angular v9 and I think they might also solve this issue, see: 373e133 and c4e039a

Wow, 2019 is coming to an end, the problem still exist

Wow, 2019 is coming to an end, the problem still exist

same for i18n and working solution

This can be fixed by providing the exported class through a factory provider. The following is an example providing MarkerClusterer from @google/markerclustererplus:

import MarkerClusterer from '@google/markerclustererplus';

export const MARKER_CLUSTERER_CLASS = new InjectionToken<new (...args: any) => MarkerClusterer>(
  'MarkerClustererPlus class from @google/markerclustererplus',
);

export function markerClustererClassFactory(): new (...args: any) => MarkerClusterer {
  return MarkerClusterer;
}

@NgModule({
  providers: [
    { provide: MARKER_CLUSTERER_CLASS, useFactory: markerClustererClassFactory },
  ],
})
export class SomeModule {}

@Injectable()
export class SomeService {
  constructor(@Inject(MARKER_CLUSTERER_CLASS) private markerClustererClass) {}
}

❯ ng --version

     _                      _                 ____ _     ___
    / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
   / △ \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | |
  / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | |
 /_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
                |___/


Angular CLI: 8.3.23
Node: 10.16.1
OS: linux x64
Angular: 8.2.14
... animations, common, compiler, compiler-cli, core, forms
... language-service, platform-browser, platform-browser-dynamic
... router

Package                            Version
------------------------------------------------------------
@angular-devkit/architect          0.803.23
@angular-devkit/build-angular      0.803.23
@angular-devkit/build-ng-packagr   0.803.23
@angular-devkit/build-optimizer    0.803.23
@angular-devkit/build-webpack      0.803.23
@angular-devkit/core               8.3.23
@angular-devkit/schematics         8.3.23
@angular/cli                       8.3.23
@ngtools/webpack                   8.3.23
@schematics/angular                8.3.23
@schematics/update                 0.803.23
ng-packagr                         5.7.1
rxjs                               6.5.4
typescript                         3.5.3
webpack                            4.39.2

Hey folks,

default exports are now working in the Ivy compiler!

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Please file a new issue if you are encountering a similar or related problem.

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AoT Compiler unable to resolve module with "export default class" #11402

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AoT Compiler unable to resolve module with "export default class" #11402

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vicb commented on Sep 7, 2016

vicb commented on Sep 8, 2016

mhevery commented on Sep 10, 2016

alexeagle commented on Sep 11, 2016

robwormald commented on Sep 11, 2016

34 remaining items

spinspume commented on May 29, 2019

SchnWalter commented on Sep 27, 2019

Ni55aN commented on Nov 12, 2019

montella1507 commented on Nov 26, 2019

niklaas commented on Jan 24, 2020

JoostK commented on Mar 15, 2020

angular-automatic-lock-bot commented on Apr 15, 2020

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