reselect VS jest

- Throws better errors in an RSC environment

- https://github.com/reduxjs/react-redux/releases/tag/v9.0.0

## Reselect 5.0:

- Switches to a new `weakMapMemoize` memoizer as default

- Renames `defaultMemoize` to `lruMemoize`

- Allows passing memoizer options direct to `createSelector`

- Many TS improvements

- https://github.com/reduxjs/reselect/releases/tag/v5.0.1

## Redux Thunk 3.0:

- Drops the default export and switches to named exports ( `{thunk, withExtraArgument}` )

- https://github.com/reduxjs/redux-thunk/releases/tag/v3.1.0

This has been a _huge_ year-long development effort!

We're thrilled to get these improvements out. The tooling and bundle improvements will help all users, and we think the features and TS changes will improve the Redux dev experience significantly.

Thank you SO MUCH to everyone who has contributed or helped test out the work!

Please file bug reports for the inevitable issues that pop up post-release!

but now I'm going off on a conf trip and going to take a very well-earned break from Redux work for December :)

reselect -> For making faster queries to store.

Reselect solves this problem by memorizing the values and only passing what’s necessary.

In addition, diagnosing bugs in how data flowed through the application (where data originated from, how it was changed, etc.) was always super painful because I had to backtrack through selectors referencing selectors referencing selectors. And updating high-level selectors risked breaking something else down the line (even with 100% business logic coverage this was a problem). (This may be chalked up to improper usage of reselect, but I'm curious to hear your thoughts. Is this a common problem?)

reselect : Selector library to optimize your store access

Reselect documentation:

Applying memoization to TypeScript and ReactJS is relatively straightforward. There are several libraries available that provide memoization functionality, such as memoize function from Lodash, reselect or hooks from ReactJS. These libraries can be installed using NPM or Yarn and used in your TypeScript and ReactJS projects.

Generally, all you would need is to have your redux store provider at the very top level of your application (You could also only wrap the components that you want to have this data available to). Then, any component rendered inside that provider can get access to the redux store. The suggested approach ever since hooks were released is to use `useSelector` and `useDispatch` within your component to get the state data that you need. Using a selector library like Reselect is prevalent and keeps your data selection tidy & handles memoization for you.

Reselect is a library for creating memoized “selector” functions. Commonly used with Redux, to slice state and provide just the necessary subtree to a React component.

GitHub | Website

Jest

you have selected a testing framework. In my case, it's Jest with Supertest

Jest, created and maintained by Facebook, is a JavaScript testing framework with a focus on simplicity. It is often recognized for its zero-configuration setup and seamless integration, especially with React applications, making it a favored choice for developers in both small-scale projects and large enterprise applications.

Jest (https://jestjs.io/)

console.error Jest encountered an unexpected token Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax. Out of the box Jest supports Babel, which will be used to transform your files into valid JS based on your Babel configuration. By default "node\_modules" folder is ignored by transformers. Here's what you can do: • If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/ecmascript-modules for how to enable it. • If you are trying to use TypeScript, see https://jestjs.io/docs/getting-started#using-typescript • To have some of your "node\_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config. • If you need a custom transformation specify a "transform" option in your config. • If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option. You'll find more details and examples of these config options in the docs: https://jestjs.io/docs/configuration For information about custom transformations, see: https://jestjs.io/docs/code-transformation

Note: I will be using Jest as testing framework throughout the examples.

We use Jest Framework for testing. Jest is not a dogma, and, of course, in its place can be any other test runner, such as Mocha or Ava. Let's focus on tests. I'll provide a short example because I don’t want to waste your time. You can find the full version here. It's crucial to read the comments in the code below. Let's go!

Jest has long been my favorite got to test runner when it comes to UI unit and integration testing. With tools like React Testing Library (Testing Library framework for React) you get the benefit of very easy to write and maintain tests, as well as a quick and efficient way to run our tests.

Jest is a well-regarded JavaScript testing framework primarily designed for React applications, although its utility extends to projects using Babel, JavaScript, Node, Angular, and Vue. Created by Facebook, Jest emphasizes ensuring the correctness of JavaScript codebases. It allows developers to write tests with a familiar, feature-rich API, making the testing process swift and enjoyable​​.