Fueling Curiosity, One Insight at a Time

Mocking useSWR directly in test cases is a little complicated and even not recommended at some places.
So the ideal way to do it is using a library Mock Service Worker. Here are the steps that helped me solve this.
1. Create a mock server using setupServer from msw/node:

const server = setupServer(
  rest.get(`/api/channels/C04UPJ9243E/members`, (req, res, ctx) => {
    return res(
      ctx.json({
        members: [{ name: "Sibtain", image: "abcd.jsp", id: 123 }],
      })
    );
  })
);

2. Start the server and after we run the test, close the server.

beforeAll(() => server.listen());
afterAll(() => server.close());

3. To ensure clean and isolated tests, reset the request handlers.

afterEach(() => server.resetHandlers());

Now our API connections are taken care of and we can render components and run the test cases.

test('render stuff, () => {
}

Resources: https://mswjs.io/

While writing Cypress test we generally create a cypress.env.json file to store the environment variables.

{
  "BASE_URL": "https://company.dev.com/",
  "USER_EMAIL": "ashwani@example.com",
  "USER_PASSWORD": "Test@12345",
}

To retrieve the value of our environment variable, we use the Cypress.env method in the test file.

const baseUrl = Cypress.env('BASE_URL');

That's all we need to do locally to use the env vars in our Cypress test.

Now for CI, we can save these environment variables as Github action secrets.

To make these environment variables accessible from Github action secrets to our test, we need to keep a few things in mind.

• Add a value of empty string to the env vars and expose the cypress.env.json file.

  {
       "BASE_URL": "",
       "USER_EMAIL": "",
       "USER_PASSWORD": "",
  }

• We need to add CYPRESS_ prefix to the env vars in the yml file.

   env:
       CYPRESS_BASE_URL: ${{ secrets.BASE_URL }}
       CYPRESS_USER_EMAIL: ${{ secrets.USER_EMAIL }}
       CYPRESS_USER_PASSWORD: ${{ secrets.USER_PASSWORD }}

Happy testing!

If Postgres logical replication is enabled via pglogical extension, below query can be used to check the size WAL Folder.
select sum(size) from pg_ls_waldir(); (Response to the query is in Bytes)

This is the folder where the WAL logs are stored, which is utilized for postgres data replication from master to slave. In case there is any lag or problems with replication the logs will get accumulating in the folder, spiking the disk storage and can cause downtime of the database it self.

In the first server-side rendering (SSR) page render, the router.query may not be populated immediately. To handle this scenario, we can add a check to ensure that the redirection happens only on the client-side, once the router.query values are available.

import { useEffect } from 'react';
import { useRouter } from 'next/router';

export const ResetPasswordPage = () => {
  const { push, query, isReady } = useRouter();
  const { username, code } = query as ResetPasswordPageQuery;
   ...
  useEffect(() => {
    if (isReady && (!username || !code)) {
      push('/login');
    }
  }, [isReady, username, code, push]);
  ...
};

Here the isReady property from useRouter is used to determine if the router is ready and router.query is populated.
This way, the initial SSR render won't trigger the redirection, and the user will be redirected to the login page only on the client-side if the necessary parameters are missing from the URL.

Tools discussed in todays session
1. https://ethereal.email/ - Email Testing
2. https://github.com/danmayer/coverband - Clean Up Legacy Unused Code
3. https://posthog.com/ - Product Analytics
4. https://miro.com/ - Collaboration Tool

Open PR from CLI
• brew install hub
• git config --global hub.protocol https
• hub pull-request (Will create PR for the current branch)

Term called fuzzy searching
fuzzy searching (more formally known as approximate string matching) is the technique of finding strings that are approximately equal to a given pattern (rather than exactly).

I learned how to use promise.all to combine multiple api calls.
Learned how to made api endpoint by using app directory and page directory in Next Js.

Learned how to implement slack bolt app with next js using the bolt http runner npm package

Learned how to use node-cron to schedule message

The Active Record Pattern popularised by Ruby on Rails goes against the modularity provided by Nest.Js.

Nest.js encourages the use of the Repository pattern.

Data Mapper/Repository pattern:

• Separates data access logic from business logic
• Data Mapper: Maps data between domain objects and the database
• Repository: Provides methods for querying and manipulating domain objects
• Promotes separation of concerns, testability, and maintainability
Active Record:

• Combines data access and business logic within domain objects
• Domain objects encapsulate database interactions
• Simplifies development by allowing direct manipulation of objects
• Can make separation of concerns and independent testing more challenging

Etag HTTP Header
- Etag (also known as entity tag) is a unique identifier for a resource
- This is used to cache the resources that are unchanged
- When a request is recieved by server, it generates response and attaches Etag
- In the subsequent request, application requests for the same resource with If-None-Match header with the value of Etag received in previous step
- Server compares the value of If-None-match header with Etag identifier value on server
- If the values match server responds with 304(Not modified) status code with the empty body
- Application can use the cached response