You cannot add properties to an object within an async function

Question

You cannot add properties to an object within an async function

I am attempting to include a fileUrl property in the order object within an async function, but I am unable to make it work properly.

My expectation is for the order object to contain a fileUrl property once added, but unfortunately, it does not seem to be working as expected.

    router.get('/my-orders/:id', isAuth, async (req, res) => {
    const id = req.params.id;

    try {
        const orders = await Order.find({ userId: id });
        if (orders.length > 0) {
            for (const order of orders) {
                const getObjectParams = {
                    Bucket: bucketName,
                    Key: order.fileName,
                }

        
                const command = new GetObjectCommand(getObjectParams);
                const url = await getSignedUrl(s3, command, { expiresIn: 3600 });
                // adding fileUrl property to order
                order.fileUrl = url;
                
                // it logs only order without fileUrl property
                console.log(order);
            }

            res.send('OK');
        }
    } catch (error) {
        console.error(error);
    }
})

javascript arrays express asynchronous promise

Answer 1

Answer №1

When working with MongoDB, it's important to remember that iterating through a cursor returned by Order.find() will provide you with MongoDB documents, not plain Javascript objects. If you need to work with plain Javascript objects for manipulation purposes, you can utilize the .toObject() method on the document.

router.get('/my-orders/:id', isAuth, async (req, res) => {
    const id = req.params.id;

    try {
        const orders = await Order.find({ userId: id });
        if (orders.length > 0) {
            for (const order of orders) {
                const getObjectParams = {
                    Bucket: bucketName,
                    Key: order.fileName,
                }

                const command = new GetObjectCommand(getObjectParams);
                const url = await getSignedUrl(s3, command, { expiresIn: 3600 });

                // Convert from MongoDB document to plain Javascript object
                const modifiedOrder = order.toObject();

                // Adding fileUrl property to order
                modifiedOrder.fileUrl = url;
                console.log(modifiedOrder);
            }

            res.send('OK');
        } else {
            res.send('No Orders Found');
        }
    } catch (error) {
        console.error(error);
        // Always send some response, even for errors
        res.sendStatus(500);
    }
});

Additionally, I've improved the request handler to ensure it always sends a response, whether there are orders found or any errors occur.

For more options and discussions, such as using .lean() and .set(), you can refer to this answer.

Answer 2

When working with MongoDB, it's important to remember that iterating through a cursor returned by Order.find() will provide you with MongoDB documents, not plain Javascript objects. If you need to work with plain Javascript objects for manipulation purposes, you can utilize the .toObject() method on the document.

router.get('/my-orders/:id', isAuth, async (req, res) => {
    const id = req.params.id;

    try {
        const orders = await Order.find({ userId: id });
        if (orders.length > 0) {
            for (const order of orders) {
                const getObjectParams = {
                    Bucket: bucketName,
                    Key: order.fileName,
                }

                const command = new GetObjectCommand(getObjectParams);
                const url = await getSignedUrl(s3, command, { expiresIn: 3600 });

                // Convert from MongoDB document to plain Javascript object
                const modifiedOrder = order.toObject();

                // Adding fileUrl property to order
                modifiedOrder.fileUrl = url;
                console.log(modifiedOrder);
            }

            res.send('OK');
        } else {
            res.send('No Orders Found');
        }
    } catch (error) {
        console.error(error);
        // Always send some response, even for errors
        res.sendStatus(500);
    }
});

Additionally, I've improved the request handler to ensure it always sends a response, whether there are orders found or any errors occur.

For more options and discussions, such as using .lean() and .set(), you can refer to this answer.

You cannot add properties to an object within an async function

Answer №1

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