Get max available ID by using DynamoDB: increase an attribute value at a DynamoDB table and returns increased value.

gistfile1.txt

// MY_META DynamoDB table has a primary key "name" and a attribute "value"
// Added a record with "lastUsedSid" as name, and a Number as value.

export function getNextValidSid (callback) {
    const params = {
        TableName: MY_META,
        Key: {
            'name': 'lastUsedSid',
        },
        UpdateExpression: 'set #v = #v + :val',
        ExpressionAttributeValues: {
            ':val': 1
        },
        ExpressionAttributeNames: {
            '#v': 'value',
        },
        ReturnValues: 'UPDATED_NEW',
    }

    docClient.update(params, (err, data) => {
        if (err) {
            console.error(`getNextValidSid: Unable to increase lastUsedSid's value at ${MISEBIG_META}. Error JSON:`, JSON.stringify(err, null, 2))
            return callback(err)
        }

        console.log(`getNextValidSid: result: `, data)
        callback(null, data.Attributes.value)
    })
}