client.query returns undefined

[daianaszwimer]

I'm executing this function on my test:

const params = {
    TableName: TABLE_NAME,
    IndexName: TREE_INDEX,
    KeyConditionExpression: "parent = :parent",
    FilterExpression : "#l = :level",
    ExpressionAttributeNames: {
        "#l": "level"
    },
    ExpressionAttributeValues: {
        ":level": this.level,
        ":parent": parent
    }
};
const result = await this.db.query(params);

And result is undefined when it should return an array of items and when it should return an empty array

I have other queries on my code that have an index that work ok, but this one has an index and a filter expression, and for some reason, it's not working as expected

Attached you can see that when I want to access result.Items I get an error because result is undefined

PS: this.db is an instance of DocumentClient

[freshollie]

Which version of the aws-sdk are you using? I'm pretty sure you need a .promise() on the end of your query?

[daianaszwimer]

@freshollie i'm using the version ^2.541.0. And yes, I'm using the promise() at the end, I forgot to clarify that. The this.db references a file that exports {query: (params) => client.query(params).promise()} (among other functions as well), so the db call is ok

[freshollie]

Very interesting. From my point of view, jest-dynalite does nothing to the actual aws-sdk module, and thus, the fact the function is returning undefined is something going on with the SDK, as Result type should always be returned from a query.

Are you able to produce a reproduction? Does this code work when you connect to a dynamodb-local instance?

[daianaszwimer]

@freshollie
I debugged and the problem seems to be related to line 54 on dynalite/actions/query.js

if (!data.KeyConditions[attr]) {
  if (isHash || Object.keys(data.KeyConditions).length > 1) {
    return db.validationError('Query condition missed key schema element: ' + attr)
  }
  return
}

!data.KeyConditions[attr] returns true but isHash || Object.keys(data.KeyConditions).length > 1 is false so it returns undefined

[freshollie]

Interesting, do you know what the code should do instead of returning undefined? Might it be worth putting in an upstream PR?

[daianaszwimer]

@freshollie idk if this answers your question but the code should return what the query needs which is a result object with the Items key that has an array with the results from the DB

[freshollie]

@daianaszwimer have you tried executing this expression against a real dynamodb instance? I have a feeling your query is wrong but the return is just missing the correct error information.

[daianaszwimer]

yes, I have :) The query works fine @freshollie