React App Sync Data with REST API After User Actions - node.js

Technology Information: ReactJS + Typescript for the frontend. REST API built with nodeJS+express that stores data in a Cloud Firestore database. The frontend React application retrieves data using the REST API.
State Management on the Frontend: I'm currently using React hooks for state management. useContext is used for managing global state (user/session information), and useReducer is used for route level state. The useReducer hook is called by the top level component in any given route.
Advice Requested:
If the user takes an action with the UI, I want to update the local state and show the appropriate changes in the UI instantly. I want to make sure the data gets saved to our backend, and only display an error message if we failed to save the data.
What's the most seamless way of handling data synchronization in this case? What's the best architecture here?
Should I make calls to the REST API from within each action in the
reducer?
What's the cleanest way to implement this throughout a large application? How should I organize my code for data synchronization?
Along the same lines, if I want to listen to changes to the user
object in the backend, and reload the user's information that's
stored in global state using the useContext hook, how should I try
to do this?
P.S. I love how seamlessly Asana syncs & saves your data. I'm wondering what are the best practices here if I want to have that seamless of an experience.

Related

Where should calculations be done in a MEAN stack app

I am building an ecommerce website for a project for my portfolio, and I wanted to know where the calculations should be done for the cart.
Normally I use react and I create a model folder, route folder and a controller folder but the way I was taught Angular it seems like the services acts like the routes and the actual calls to the database are done in the node server file which I am sure I could separate into a separate controller file. My question is where should the calculations for the cart be done before I send the order to the database? I thought about doing it in the cart component before the order is place or should it be done in the services or in the backend in the controller? I am just trying to figure out what is the standard
When writing an Angular app, I think it is important to adhere to the following principles that:
Components - should have a single responsibility for simple view logic only, shouldn't reach out to the server, and shouldn't do complex calculations and/or logic that is not related to the view.
Services - should have a single responsibility for (reusable/shared) and complex logic, to do outbound communication and reach out to the server, and to act as data stores (using BehaviorSubjects).
Therefore, if your calculations are needed to update the view of the cart, I would vote that these calculations need to be made at the component. If your calculations are needed to update the items or the request to be sent to the server, they need to be made at the service.
Remember, the component "shouldn't know" how the data comes to it or how it is manipulated or sent to the server. The component should only know, given any data - how to present it in the view, and shouldn't "worry about" how that data came to it. Similarly, the component shouldn't know how the data is calculated before being sent to the server, and this would fall within the responsibility of the service that works with and processes the cart data and builds the request to the server.
However, you have to always consider the security of your app, and if a malicious data modification at the client side can affect your cart. If such caculations affect the app's security - they should at least be validated at the server if not fully delegated to it.
I don't know the calculation you need exactly, but since it is an e-commerce website I assume it is simple math such as the total payment amount of checkout.
The main role of the server is communicating to the database. If a task does not involve interacting with data, you can do the calculations on the client-side. Leaving details on client-side allows you to have access to details of your formula, and reduce the communication time between client and server.

MERN Stack, how big of a role can redux play?

My project involves somewhat of a checklist. Initially, I used Redux to keep track of the state (whether something is checked off or not). Later I implemented a backend node server and a mongo database, and I load data from the database every time I fire up or refresh localhost. Since the checkoffs directly modify the elements in the database, there's not a whole lot Redux is doing that pre-emptive loading isn't already doing.
So my main question is that if the data is fetched from the backend the moment I start everything up, what else can I use Redux for in this case? I know my project might be too small and simple to give out a good answer, but I'd still like to know possibilities if possible.
No matter, your data is coming form backend but you still need redux for many reasons. Redux is not about just for storing data but it best for performance. Let discuss it with use cases.
Suppose you have main component of COMPANY and that is fetching data from API/backend and data cam to COMPANY component and same data is required to your ADMIN component and you again call network for data, and you know fetching data for each component from backend is very heavy and make your application slow.
So the best solution is to fetch all you data one time and save them in REDUX STORE and distribute data over your components.
MAIN ROLE:
1- Easy to manage data and state
2- Optimization and performace improvement with SELECTORS
3- Debugging is very easy
4- Easy to track data

External API Calls server or client side?

I'm currently working on an analytics webapp with a react frontend and node (express) backend.
Describing the functionality in a nutshell:
A user will be able to login on the website, search for a YouTube username and then the YouTube API is called, the data will be stored in a mysql db via my express API and also the data will be used to calucalte some statistics which afterwards are displayed in a dashboard.
Now I was wondering if I should:
Call the YouTube API from the frontend, i.e. inside my react code, do the calculations display them and and then store it in the DB via my express API.
Or, from the react app call an endpoint in my express API that will then call the YouTube API, store the data in the DB and then pass on the data to my react app.
Are there any best practices or up-/downsides to either approach?
When answering questions like these, it's important to remember that the client-side is different for each and every user that visits your website, their internet speed, their GPU & CPU power, etc., but the server is most commonly held in a stable container and much more powerful than a client.
The proper way would be the following:
1. Obtain a search query from a client
Meaning you should get the user's search query from an input, or any other form of control (text area, checkbox, etc.), this way client is doing the least business logic, as it should. The client should always focus more on UI / UX rather than business logic.
2. Send query to the server
Let the server use the query you've just obtained from client, call the youtube api from the server (either explicitly using Axios, or find a node.js youtube library), and do all the necessary calculation on the backend
3. Send processed data to the client
Let client receive the data in the form which is ready for use (iterations, mappings, etc.) - again separating concerns, server - business logic, client - UI / UX
Now to be fair, the example you have will most commonly be done all on the client-side, since it is not as computationally heavy as other enterprise examples, but this is a good rule to follow for big projects, and no one would really complain if you did it this way, since it would be the proper way.

how to use cache data in mvc architecture

As the title suggest. I'm trying to figure out where I should cache data in my node.js application.
I'm using a express.js and controllers to handle the routes in the application. The controller for a particular route will get data via the model layer using REST API and then it uses handlebars for the view rendering on the server.
For this particular route, I'm displaying a menu and the data I have got for this has been done in the model and a remote REST call.
When the user select different items in the menu, I do not want to make a new REST call to get the same data for the menu again, I just need to get the data for this menu once since it will never change.
I need to find out a way to cache it, but do not know where I should implement it?
Best Regards
You could just cache the response from the REST API or DB lookup using a memory-store like Redis or Memcached, both have good modules available on npm - (Redis, memcached).
You would need to attempt to fetch the data from the memory-store (in your controller), if no matching data was found, you would make the request to the API or database to get the data, and then store it in your chosen memory-store so future requests will hit the cache.
note: There are also some pure JavaScript caches available such as memory-cache or lru-cache if you don't want to add an additional application.

Posting Firebases's thirdpartyuserdata object to the server

I'm using Firebase and the SimpleLogin to allow users to login via Google, Twitter etc.
I'd like to use some of the thirdpartyuserdata object to create a user profile for my application which runs on Node.
Currently I'm posting this data to the server so that I can add to it and create the profile object, but I wondered if there's a better way of doing this - is there something I can call server side to get this thirdpartyuserdata without having to post it from the client?
Start by considering that your "server" is actually just another consumer of Firebase data. Since FirebaseSimpleLogin is simply a token generator with some fancy tools for doing OAuth, and because this happens completely client-side, there is nothing to consume about this.
If you want to consume the data at the server, you will either need to POST it, as you have done, or use Firebase to transfer the information. You'll find that a queue approach can save you a large amount of code, as this allows you to use Firebase as the API, and avoid creating RESTful services in Node, and all the baggage that comes with that.
The idea of a queue is simply that you push data into Firebase at one client and read it out (and probably delete it) at the intended recipient (in this case your node worker).

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