Async / await is not working (javascript / DynamoDB)

Question

I have a DynamoDB Put request wrapped into an async function.

 async function putter(param1, param2) {

        const paramsPut = {
            TableName: MyTableName,
            Item: {
                "hashKey": param1,
                "sortKey": param2,
            }
        };

        dynamodb.put(paramsPut, function(err, data) {

            if (err) {
                console.log("Failure")
                console.log(data)
                return data
            }
            else {
                console.log("Success")
                console.log(data)
                return data
            }
        });
    };

The return for the async funtion is placed in the response function - this the should provide back a promise upon put operation was performed (either sucessfully or not sucessfully).

I then invoke this async put function from another async function:

    var param1 = "50";
    var param2 = "60";


    async function main() {

        await putter(param1 , param2)
        console.log("Feedback received")

    }

When I invoke this aysnc main function I would expect it to provide the Success statement from the put function prior to writing "Feedback received" as it should await the put function response.

However my console logs the "Feedback received" prior to logging the "Success" statement in the put async function which I was awaiting.

What am I missing here? Thanks for your support!

Answer 1

Try to change your code like follows:

try {
    const data = await dynamodb.put(paramsPut).promise()
    console.log("Success")
    console.log(data)
    return data
} catch (err) {
    console.log("Failure", err.message)
    // there is no data here, you can return undefined or similar
}

Almost every function from AWS SDK has the promise() variant to return the result as a Promise. Then you can just await the Promise. Don't mix callbacks with promises (async/await) - it makes the code hard to read, it's better to stick with one technique everywhere.