使用AWS Amplify模块化包时Appsync订阅功能失效求助

背景 #

我有一个React应用，希望将单体包aws-amplify替换为@aws-amplify/<package-name>形式的模块化包。使用单体包时所有功能均正常运行，当前需要用到Auth、带订阅功能的GraphQL API。

导入的模块化包版本 #

"@aws-amplify/core": "^4.7.2"
"@aws-amplify/api": "^4.0.51"
"@aws-amplify/auth": "^4.6.4"
"@aws-amplify/pubsub": "^4.5.1" // 该包似乎是GraphQL订阅所需

配置代码 #

我调用了Amplify的register函数（仅导入包无法生效），随后调用core的config函数向已注册模块传入配置：

Amplify.register(Auth)
Amplify.register(API)
Amplify.register(PubSub)

Amplify.configure({
    // AUTH
    aws_cognito_region: region, // (required) - Region where Amazon Cognito project was created
    aws_user_pools_id:  userPoolId, // (optional) -  Amazon Cognito User Pool ID
    aws_user_pools_web_client_id: userPoolClientId, // (optional) - Amazon Cognito App Client ID (App client secret needs to be disabled)
    aws_cognito_identity_pool_id: identityPoolRef, // (optional) - Amazon Cognito Identity Pool ID
    aws_mandatory_sign_in: "disabled", // (optional) - Users are not allowed to get the aws credentials unless they are signed in

    // API
    aws_appsync_region: region, // (optional) - AWS AppSync region
    aws_appsync_graphqlEndpoint: graphqlUrl, // (optional) - AWS AppSync endpoint
    // 更像是默认认证类型，可在单个查询中覆盖，参考创建租户逻辑
    aws_appsync_authenticationType: "AMAZON_COGNITO_USER_POOLS", // (optional) - Primary AWS AppSync authentication type

    // 通常我们只发送不包含用户名及JWT中其他编码信息的访问密钥
    // 因此我们自行在请求头中携带ID Token
    API: {
        graphql_headers: async () => {
            try {
                const session = await Auth.currentSession();
                if(session) {
                    return {
                        Authorization: session.getIdToken().getJwtToken(),
                    };
                }
            } catch(e) {
                console.warn(e)
            }
        },
    }
});

报错信息 #

PubSub模块尝试实例化MQTT IoT客户端时失败，报错如下：

index.ts:939 Uncaught TypeError: Object prototype may only be an Object or null: undefined
at setPrototypeOf (<anonymous>)
at extendStatics (index.ts:939:1)
at __extends (index.ts:939:1)
at AWSIotProvider.ts:23:1
at ./node_modules/@aws-amplify/pubsub/lib-esm/Providers/AWSIotProvider.js (AWSIotProvider.ts:59:1)
at options.factory (react refresh:6:1)
at __webpack_require__ (bootstrap:24:1)
at fn (hot module replacement:62:1)
at ./node_modules/@aws-amplify/pubsub/lib-esm/Providers/index.js (constants.ts:100:1)
at options.factory (react refresh:6:1)

疑问 #

我并不需要IoT客户端，同时对以下几点存在疑问：

• AWS配置属性混乱：支持作用域配置，但在模块化包中无法生效（模块会跨属性查找，作用域配置下无法找到对应属性），为何不彻底移除作用域配置？
• 依赖关系未文档化：没有任何说明提到"使用订阅功能需要PubSub包"。
• PubSub实例为何要实例化MQTT IoT客户端？

更新 #

已在Github提交相关issue。

内容的提问来源于stack exchange，提问作者pfried