I'm trying to consolidate my DynamoDB functions that query and put items to my DB, however the typescript is causing me issues.

Original

export const getResultFromDb = async (): Promise<QueryCommandOutput> => {

  const command = new QueryCommand({
    ...
  });

  try {
    return await client.send(command);
  } catch (err) {
    // log out
  }
};

export const addItemToDb = async (data: any): Promise<PutItemCommandOutput> => {
  const command = new PutItemCommand({
    ...
  });

  try {
    return await client.send(command);
  } catch (err) {
    // Log out
  }
}

I have attempted to move the main try/catch logic into its own function

const queryDb = async <T>(command: any): T => {
  try {
    return await client.send(command);
  } catch (err) {
    // Log out
  }
}

with the idea of specifying my output types like

export const getResultFromDb = async (): Promise<QueryCommandOutput> => {

  const command = new QueryCommand({
    ...
  });

  return await queryDb<QueryCommandOutput>(command);
};

export const addItemToDb = async (data: any): Promise<PutItemCommandOutput> => {
  const command = new PutItemCommand({
    ...
  });

  return await queryDb<PutItemCommandOutput>(command);
}

Asking AI about the types for the command arg, it suggested that I should use @aws-sdk/smithy-client's "Command" like

const queryDb = async <T>(command: Command<any, T, any>): T => {

but the IDE didn't like this very much:

TS2345: Argument of type Command<any, T, any, any, any> is not assignable to parameter of type
Command<ServiceInputTypes, any, ServiceOutputTypes, ServiceOutputTypes, SmithyResolvedConfiguration<HttpHandlerOptions>>
Types of property middlewareStack are incompatible.
Property identifyOnResolve is missing in type MiddlewareStack<any, T> but required in type MiddlewareStack<any, ServiceOutputTypes>
middleware. d. ts(432, 5): identifyOnResolve is declared here

I'm trying to consolidate my DynamoDB functions that query and put items to my DB, however the typescript is causing me issues.

Original

export const getResultFromDb = async (): Promise<QueryCommandOutput> => {

  const command = new QueryCommand({
    ...
  });

  try {
    return await client.send(command);
  } catch (err) {
    // log out
  }
};

export const addItemToDb = async (data: any): Promise<PutItemCommandOutput> => {
  const command = new PutItemCommand({
    ...
  });

  try {
    return await client.send(command);
  } catch (err) {
    // Log out
  }
}

I have attempted to move the main try/catch logic into its own function

const queryDb = async <T>(command: any): T => {
  try {
    return await client.send(command);
  } catch (err) {
    // Log out
  }
}

with the idea of specifying my output types like

export const getResultFromDb = async (): Promise<QueryCommandOutput> => {

  const command = new QueryCommand({
    ...
  });

  return await queryDb<QueryCommandOutput>(command);
};

export const addItemToDb = async (data: any): Promise<PutItemCommandOutput> => {
  const command = new PutItemCommand({
    ...
  });

  return await queryDb<PutItemCommandOutput>(command);
}

Asking AI about the types for the command arg, it suggested that I should use @aws-sdk/smithy-client's "Command" like

const queryDb = async <T>(command: Command<any, T, any>): T => {

but the IDE didn't like this very much:

TS2345: Argument of type Command<any, T, any, any, any> is not assignable to parameter of type
Command<ServiceInputTypes, any, ServiceOutputTypes, ServiceOutputTypes, SmithyResolvedConfiguration<HttpHandlerOptions>>
Types of property middlewareStack are incompatible.
Property identifyOnResolve is missing in type MiddlewareStack<any, T> but required in type MiddlewareStack<any, ServiceOutputTypes>
middleware. d. ts(432, 5): identifyOnResolve is declared here

• node.js
• typescript
• amazon-web-services

• Great to see TypeScript giving C++ compiler teams a little competition in the obfuscation department. Also, I think that @aws-sdk/smithy-client is deprecated and has moved to @smithy/smithy-client. – jarmod Commented Mar 25 at 15:26

1 Answer 1

You can reply on type of client.send function:

import { DynamoDBClient } from '@aws-sdk/client-dynamodb';

const queryDB: DynamoDBClient['send'] = async (
  command: Parameters<DynamoDBClient['send']>[0],
) => {
  try {
    return await client.send(command);
  } catch (e) {
    console.error(e);
  }
};

Now, you can use queryDB as the .send function:

const command = new PutItemCommand({
  ...
});

const output = await queryDB(command);
//    ^? PutItemCommandOutput