Function flattenProviders

packages/core/testing/src/test_bed_compiler.ts:1205–1221

(
  providers: Array<Provider | InternalEnvironmentProviders>,
  mapFn: (provider: Provider) => any = identityFn,
)

): T[];
function flattenProviders(providers: Array<Provider | InternalEnvironmentProviders>): Provider[];
function flattenProviders(
  providers: Array<Provider | InternalEnvironmentProviders>,
  mapFn: (provider: Provider) => any = identityFn,
): any[] {
  const out: any[] = [];
  for (let provider of providers) {
    if (isEnvironmentProviders(provider)) {
      provider = provider.ɵproviders;
    }
    if (Array.isArray(provider)) {
      out.push(...flattenProviders(provider, mapFn));
    } else {
      out.push(mapFn(provider));
    }
  }
  return out;
}

function getProviderField(provider: Provider, field: string) {
  return provider && typeof provider === 'object' && (provider as any)[field];