How to configure NGRX/Data for AOT compilation

Question

I have a standard setup from the NGRX data docs with one Entity. Everything works with JIT but when I do AOT then I get following Error:

...
Function expressions are not supported in decorators in 'entityConfig'
'entityConfig' references 'ɵ0'
...
Consider changing the function expression into an exported function.

My entity config:

const entityMetadata: EntityMetadataMap = {
  Identifiers: {}
};

export const entityConfig = {
  entityMetadata
};

My module:

...
import { entityConfig } from './store/entity-metadata';

@NgModule({
  imports: [CommonModule, EntityDataModule.forRoot(entityConfig)]
})
...

The error is thrown here: EntityDataModule.forRoot(entityConfig)

Versions:

"@angular/core": "^8.1.1",
"@ngrx/data": "^8.6.0",
"@ngrx/store": "^8.6.0",

Answer 1

The problem can be solved by using the EntityDefinitionService like this:

import { EntityDefinitionService } from '@ngrx/data';
import { entityMetadata } from './store/entity-metadata';

@NgModule({
  imports: [CommonModule]
})
export class NotLazyLoadedFeatureModule {
  constructor(private eds: EntityDefinitionService) {
    eds.registerMetadataMap(entityMetadata);
  }
}

But the EntityDefinitionService expects the EntityMetadataMap directly, without wrapping it in an Object.

export const entityMetadata: EntityMetadataMap = {  -> Use this
  Identifiers: {}
};

/* export const entityConfig = {  -> Not needed anymore
  entityMetadata
};*/

Worth mentioning is that I have the Store split up to multiple modules. They are technically not lazy-loaded but my app-store.module.ts looks like this:

@NgModule({
  declarations: [],
  imports: [
    CommonModule,
    StoreModule.forRoot({}),
    EffectsModule.forRoot([]),
    EntityDataModule.forRoot({}), <- Only needed once
    NotLazyLoadedFeatureModule, <- Import not lazy loaded modules here
    StoreDevtoolsModule.instrument()
  ]
})
export class AppStoreModule {}

Comprehensive explanation about the difference between JIT and AOT:
https://gist.github.com/chuckjaz/65dcc2fd5f4f5463e492ed0cb93bca60

Answer 2

that's a known issue if you use a reducer as an arrow function. please read this part: https://ngrx.io/guide/store/reducers#creating-the-reducer-function

Note: The exported reducer function is necessary as function calls are not supported by the AOT compiler.

you have to wrap every reducer with a proper javascript function.