DynamoDB: Increment Counter (Guide w/ Code Examples)

To increment a counter in DynamoDB using the JavaScript SDK, you can use the update method and provide an update expression that uses the ADD function to increase the counter's value. Here is an example of how to increment a counter named "counter" by 1:

var params = {
    TableName: "myTable",
    Key: { "id": { N: "123" } },
    UpdateExpression: "ADD counter :val",
    ExpressionAttributeValues: { ":val": { N: "1" } },
    ReturnValues: "UPDATED_NEW"
};

dynamodb.update(params, function(err, data) {
    if (err) {
        console.error("Unable to update item. Error JSON:", JSON.stringify(err, null, 2));
    } else {
        console.log("UpdateItem succeeded:", JSON.stringify(data, null, 2));
    }
});