How do I increment counter field by 1 using UpdateCommand

Question

I'm trying to make a rate limiter and I'm having trouble finding documentation on UpdateCommand. Right now I'm trying to increment the counter field by 1 everytime I make a request with the same ip address.

https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/classes/_aws_sdk_lib_dynamodb.updatecommand-1.html

Here is what I tried

const command = new UpdateCommand({
    TableName: tableName,
    Key: {
        ipAddr: sourceIp
    },
    UpdateExpression: "set counter = Add :counter counter",
    ExpressionAttributeValues: {
        ":counter": 1,
    },
    ReturnValues: "ALL_NEW",
});

Answer 1

This should be it:

const command = new UpdateCommand({
    TableName: tableName,
    Key: {
        ipAddr: sourceIp
    },
    UpdateExpression: "ADD counter :counter",
    ExpressionAttributeValues: {
        ":counter": 1,
    },
    ReturnValues: "ALL_NEW",
});