将TypeScript类转为Lambda Layer时遇exports未定义错误求助

我尝试把下面这个AthenaHelper TypeScript类做成Node.js的Lambda Layer：

import { Athena } from "aws-sdk";

export class AthenaHelper {
  private athena = new Athena();

  public queryAthena = async (
    databaseParams: Athena.StartQueryExecutionInput
  ) => {
    const { QueryExecutionId: queryExecutionId } =
      (await this.athena.startQueryExecution(databaseParams).promise()) ?? {};

    if (!queryExecutionId) {
      throw new Error("No query execution ID");
    }

    const params = {
      QueryExecutionId: queryExecutionId,
    };

    // 等待查询完成
    await this.waitForQueryCompletion(queryExecutionId);

    // 以JSON格式获取Athena查询结果
    const results = await this.getQueryResultsInJsonFormat(params);

    return results;
  };

  private waitForQueryCompletion = async (
    queryExecutionId: string | undefined
  ) => {
    try {
      if (!queryExecutionId) {
        throw new Error("No query execution ID");
      }
      let state: string | null | undefined = null;
      while (
        state !== "SUCCEEDED" &&
        state !== "FAILED" &&
        state !== "CANCELLED"
      ) {
        await new Promise((res) => setTimeout(res, 1000));

        const { QueryExecution } = await this.athena
          .getQueryExecution({
            QueryExecutionId: queryExecutionId,
          })
          .promise();

        state = QueryExecution?.Status?.State;
      }
      return state;
    } catch (error) {
      throw error;
    }
  };

  private getQueryResultsInJsonFormat = async (
    params: Athena.GetQueryResultsInput
  ): Promise<Record<string, string | null>[]> => {
    const result: Athena.GetQueryResultsOutput = await this.athena
      .getQueryResults(params)
      .promise();

    const columnInfo: Athena.ColumnInfo[] =
      result.ResultSet?.ResultSetMetadata?.ColumnInfo || [];

    const rows =
      // 第一行是列名，这里跳过
      result.ResultSet?.Rows?.slice(1).map((row) => {
        const rowData: Record<string, string | null> = {};
        row.Data?.forEach((data, index) => {
          rowData[columnInfo[index].Name] = data?.VarCharValue || null;
        });
        return rowData;
      }) || [];
    return rows;
  };
  public helloWorld() {
    console.log("Hello World");
  }
}

用tsc编译成原生JavaScript后上传到Lambda Layer，然后运行下面的Lambda函数：

exports.handler = async (event, context) => {
  try {
  
  const AthenaHelper = require('/opt/nodejs/AthenaHelper');
  
  const athenaHelper = new AthenaHelper()
  
  athenaHelper.helloWorld()
    return {
        statusCode: 200,
        body: 'Hello, World!'
    };
  } catch (error) {
    console.log('error', JSON.stringify(error))
  }
};

执行时出现错误：

{
  "errorType": "ReferenceError",
  "errorMessage": "exports is not defined in ES module scope",
}

我的TS Config配置如下：

{   "compilerOptions": {     "lib": ["es2018", "dom"]   } } 

求解决建议，有没有人试过把自定义TypeScript类导出为Lambda Layer？

这个错误的核心是编译后的JS文件是ES模块格式，但Lambda里用CommonJS的require()去加载，导致模块系统冲突。下面是具体的修复步骤：

1. 修改TypeScript配置，编译为CommonJS模块 #

更新你的tsconfig.json，明确指定模块格式为CommonJS，同时补充必要的编译选项：

{
  "compilerOptions": {
    "lib": ["es2018"],
    "module": "CommonJS",
    "target": "ES2018",
    "outDir": "./dist",
    "esModuleInterop": true,
    "skipLibCheck": true,
    "strict": false
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules"]
}

• module: "CommonJS"：强制编译成Lambda兼容的CommonJS格式，避免生成ES模块的export语法
• outDir：指定编译后的文件输出目录，方便打包上传
• esModuleInterop：解决CommonJS和ES模块之间的兼容性问题

2. 调整Lambda函数的导入方式 #

TypeScript编译CommonJS后，类会挂在exports对象上，需要修改导入语句：

// 解构导入类
const { AthenaHelper } = require('/opt/nodejs/AthenaHelper');
// 或者如果编译后是默认导出，用下面的写法：
// const AthenaHelper = require('/opt/nodejs/AthenaHelper').default;

3. 正确打包Lambda Layer #

• 编译TypeScript：执行tsc命令，确保编译后的文件输出到dist目录
• 打包Layer：将dist目录下的文件放到nodejs文件夹中（Lambda Layer的Node.js文件必须放在nodejs目录下），然后压缩成zip包上传
  示例目录结构：

  lambda-layer.zip
  └── nodejs
      └── AthenaHelper.js
  

4. 备选方案：改用ES模块格式 #

如果想保持ES模块，需要：

• 在Lambda函数的根目录添加package.json，声明"type": "module"
• 修改Lambda代码为ES模块的import语法：

  export const handler = async (event, context) => {
    try {
      import AthenaHelper from '/opt/nodejs/AthenaHelper';
      const athenaHelper = new AthenaHelper();
      athenaHelper.helloWorld();
      return { statusCode: 200, body: 'Hello, World!' };
    } catch (error) {
      console.log('error', JSON.stringify(error));
    }
  };
  

  同时确保TypeScript编译时module设置为ESNext或ES2020，并且编译后的JS文件使用export default语法。

内容的提问来源于stack exchange，提问作者Coder Noob