NgModule嵌套forRoot

问题描述

考虑到有一个模块

@NgModule({
    imports: [
        Ng2Webstorage.forRoot({ prefix: 'SOME_PREFIX' }),
        FooModule.forRoot(...),
        BarModule,
    ],
    exports: [
        Ng2Webstorage,
        FooModule,
        BarModule,
    ]
})
class FeatureModule {
    static forRoot(config): ModuleWithProviders {
        return {
            ngModule: FeatureModule,
            providers: [...]
        };
    }
}

如何动态地将prefix传递给Ng2Webstorage.forRoot?喜欢:

How can it pass prefix to Ng2Webstorage.forRoot dynamically? Like:

@NgModule({
    imports: [
        BarModule,
    ],
    exports: [
        Ng2Webstorage,
        FooModule,
        BarModule,
    ]
})
class FeatureModule {
    static forRoot(config): ModuleWithProviders {
        return {
            ngModule: FeatureModule,
            imports: [
                Ng2Webstorage.forRoot({ prefix: config.name }),
                FooModule.forRoot(config.foo)
            ],
            providers: [...]
        };
    }
}

...
imports: [FeatureModule.forRoot({ name: `ANOTHER_PREFIX` }), ...]
...

是否可以嵌套forRoot调用?

ModuleWithProviders似乎不接受imports.

推荐答案

是的，您是对的.我们无法将imports传递给ModuleWithProviders导入.

Yes, you're right. We can't pass imports to ModuleWithProviders import.

以下是angular如何从此类导入中收集数据的信息:

Here is how angular collects data from such import:

} else if (importedType && importedType.ngModule) {
    const moduleWithProviders: ModuleWithProviders = importedType;
    importedModuleType = moduleWithProviders.ngModule;
    if (moduleWithProviders.providers) {
      providers.push(...this._getProvidersMetadata(
          moduleWithProviders.providers, entryComponents,
          `provider for the NgModule '${stringifyType(importedModuleType)}'`, [],
          importedType));
}

https://github.com/angular/angular/blob/4.3.x/packages/compiler/src/metadata_resolver.ts#L448-L456

我们可以覆盖 Ng2Webstorage.forRoot中定义的提供程序()通过在ModuleWithProviders.providers内传递相同的提供程序，如下所示:

We can override provider declated within Ng2Webstorage.forRoot() by passing the same provider within ModuleWithProviders.providers like this:

import {Ng2Webstorage, WEBSTORAGE_CONFIG} from 'ngx-webstorage';

@NgModule({
  imports: [
    Ng2Webstorage.forRoot()
  ],
  ...
})
export class FeatureModule {
  static forRoot(config): ModuleWithProviders {
    return {
      ngModule: FeatureModule,
      providers: [
        { provide: WEBSTORAGE_CONFIG, useValue: config }
      ]
    };
  }
}

这篇关于NgModule嵌套forRoot的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！