deleteFriendByValue.js

async function deleteFriendByValue(friendName) {
  const Key = { id: "1234" };
  
  // fetch the document
  let result = await DynamoDB.get({
    TableName,
    Key
  }).promise();
  
  // Delete the value from the set. This operation is idempotent and will not produce an error if the value(s) are missing.
  const { err, data } = await updateWithErrorWrapper({
    TableName,
    Key,
    UpdateExpression: `DELETE friends :valuesToRemove`,
    ExpressionAttributeValues: {
      ":valuesToRemove": DynamoDB.createSet([friendName])
    }
  });
  
  if (err) {
    console.error("unhandled error: " + err);
    return false;
  }
  return true;
}