Function injectInjectorOnly

packages/core/src/di/injector_compatibility.ts:93–120

(
  token: ProviderToken<T>,
  flags = InternalInjectFlags.Default,
)

  flags?: InternalInjectFlags,
): T | null;
export function injectInjectorOnly<T>(
  token: ProviderToken<T>,
  flags = InternalInjectFlags.Default,
): T | null {
  const currentInjector = getCurrentInjector();
  if (currentInjector === undefined) {
    throw new RuntimeError(
      RuntimeErrorCode.MISSING_INJECTION_CONTEXT,
      ngDevMode &&
        `The \`${stringify(token)}\` token injection failed. \`inject()\` function must be called from an injection context such as a constructor, a factory function, a field initializer, or a function used with \`runInInjectionContext\`.`,
    );
  } else if (currentInjector === null) {
    return injectRootLimpMode(token, undefined, flags);
  } else {
    const options = convertToInjectOptions(flags);
    // TODO: improve the typings here.
    // `token` can be a multi: true provider definition, which is considered as a Token but not represented in the typings
    const value = currentInjector.retrieve(token as PrimitivesInjectionToken<T>, options) as T;
    ngDevMode && emitInjectEvent(token as Type<unknown>, value, flags);
    if (isNotFound(value)) {
      if (options.optional) {
        return null;
      }
      throw value;
    }
    return value;
  }
}

/**
 * Generated instruction: injects a token from the currently active injector.