Tutorials on Reactdom

Code dependencies are like Lego's . We're able to pull in other people's code; combining and stacking different packages together to fulfill our goals. Using dependencies greatly reduces the complexity of developing software. We can take advantage of the hard work someone has already done to solve a problem so we can continue to build the projects we want. A development pipeline can have multiple kinds of code dependencies: In JavaScript, we have a package.json file that holds metadata about our project. package.json can store things like our project name, the version of our project, and any dependencies our project has. Dependencies, devDependencies, and peerDependencies are properties that can be included in a package.json file. Depending on the instance where code will be used changes the type of dependency a package is. There are packages that our users will need to run our code. A user is someone not directly working in our code-base. This could mean a person interacting with an application we wrote, or a developer writing a completely separate library. In other words, this is a production environment. Alternatively, there are packages that a developer or system only needs while working in our code. For example linters, testing frameworks, build tools, etc. Packages that a user won't need, but a developer or build system will need.

In the previous post , we created a unit test for a function. In this post, we're going to create a unit test for a component using @testing-library/react . Since we're using Create React App the React Testing Library is already installed in our dependencies. If you don't have it, install the package using: We will create a Greetings component with the greetings text inside and a button for sending friendly waves 😊

Tests make sure that changes in code don't break its functionality. For testing an app, we need a test runner. Create React App provides us a test runner called jest . Let's create a new app and inspect what it contains. The src directory contains all the app code and a file called App.test.tsx . This file contains a test that makes sure that the App component renders a link:

📰 In this post, we will learn about render(), a core function of ReactDOM. Along with this, we will also take a closer look at the reconciliation process, how ReactDOM works under the hood, and it's use-cases.