当键不是 Node.js 和 typescript 的分区或排序键时，如何从 dynamo db 过滤数据？

Question

My table looks like [alias, inheritedLdap, LdapGroup ] here alias is the string and the LdapGroup is the List form eg: [{S:aws}]. So basically my use case is to get the list of aliases whose ldapGroup is aws. Here the alias is the partition key, we don't have the sort key. So I need to write a method which takes the ldapGroup as the parameter and filter the list of the alias when the ldapGroup is aws. But ldapGroup doesn't contain scalar values. I tried to implement the code but its failing when I try to compile,

public async getMemberList(): Promise<any> {
      const input: any = {
      TableName: UserInfoDao.TABLE_NAME, // use this from the constants
      ProjectionExpression: "alias",
      FilterExpression: "#l = :ldapGroups",
      ExpressionAttributeNames: {
         "#l": "ldapGroups"
       },
      ExpressionAttributeValues: {
        ":ldapGroups": "PPOA"
       }
    };
    try {
       const ddbClient = DynamDBClient.getInstance();
      return await ddbClient.scan(input);
    } catch (error) {
     const message = `ERROR: Failed to retrieve alias for given ldapGroups:
     ERROR: ${JSON.stringify(error)}`;
    error.message = message;
    throw error;
  } 
}

But when I use the ScanCommandOutput and ScanCommadInput in my code instead of any, its shows the error that the

Type 'Record<string, AttributeValue>[] | undefined' is not assignable to type 'ScanCommandInput'.   Type 'undefined' is not assignable to type 'ScanCommandInput'
Property '$metadata' is missing in type 'Request<ScanOutput, AWSError>' but required in type 'ScanCommandOutput'. 

Can someone help me with this one.

I am expecting whether my approach is correct or not

Answer 1

This works for me, I made some edits you your example:

import { DynamoDBClient } from "@aws-sdk/client-dynamodb";
import { ScanCommand, ScanCommandInput } from "@aws-sdk/lib-dynamodb";

const client = new DynamoDBClient({
    region: 'eu-west-1',
});

class MyClass {

    public getMemberList(): Promise<any> {

        const input: ScanCommandInput = {
            TableName: 'Test1',
            // ProjectionExpression: "alias",
            FilterExpression: "contains(#l, :ldapGroups)",
            ExpressionAttributeNames: {
                "#l": "ldapGroups"
            },
            ExpressionAttributeValues: {
                ":ldapGroups": "aws"
            }
        };

        try {
            return client.send(new ScanCommand(input))
        } catch (error) {
            const message = `ERROR: Failed to retrieve alias for given ldapGroups: ERROR: ${JSON.stringify(error)}`;
            error.message = message;
            throw error;
        }
    }

}

const c = new MyClass();
c.getMemberList().then(res => console.log(res)).catch(err => console.log(err));