How to Fix Unexpected Token Errors When Rendering React Components in TypeScript

Overcome syntax errors while testing React components in TypeScript by ensuring proper file extension usage. Learn how to solve common rendering issues effectively. --- This video is based on the question https://stackoverflow.com/q/66177174/ asked by the user 'Alex Ironside' ( https://stackoverflow.com/u/7055769/ ) and on the answer https://stackoverflow.com/a/66178542/ provided by the user 'pmoleri' ( https://stackoverflow.com/u/488012/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Error while trying to render a react component for tests Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/licensing The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- Solving the Unexpected Token Error in React Component Tests Developing applications with React and TypeScript is a common trend among developers, combining both the expressive capabilities of components and the type safety provided by TypeScript. However, when it comes to testing, you might encounter various errors that can trip you up, particularly when rendering components. One such error is the infamous Unexpected token error. In this guide, we will explore this issue and provide a clear solution to help you get back on track. The Problem: Understanding the Error Imagine you are trying to use the create function from react-test-renderer to render a React component, but you are met with an annoying syntax error. Here is a simplified version of the code you might be running into issues with: [[See Video to Reveal this Text or Code Snippet]] When running your tests, you might see an error message similar to this: [[See Video to Reveal this Text or Code Snippet]] Why does this happen? The issue stems from the TypeScript compiler not recognizing your JSX syntax - the HTML-like syntax used in React. This oversight is often related to the file extension you are using. The Solution: Ensure Proper File Extensions Check Your File Extension The first step in resolving this error is to ensure that the file containing your component uses the correct extension. For TypeScript files that include JSX syntax, the file extension should be .tsx. Here’s what you need to do: Renaming the file: If your file is currently named something like MyComponent.ts, rename it to MyComponent.tsx. Edit your imports: Ensure that any import paths are pointing to the correct .tsx files as well. Why Use .tsx? Choosing the .tsx extension is crucial because it tells the TypeScript compiler to process JSX syntax, which is not recognized in standard .ts files. Here are a few reasons to stick with .tsx for files containing JSX: Compatibility: It ensures that all the JSX code is properly compiled to JavaScript, allowing you to utilize React components without issues. Type Safety: It retains the type-safety benefits of TypeScript while working with React. Final Steps: Test Your Code After changing the file extension to .tsx, re-run your test cases to confirm that the Unexpected token error is resolved. If all goes well, your component should render successfully without any issues. Conclusion Encountering errors when working with React components in TypeScript can be frustrating, but understanding the cause of these errors can save you a lot of time and headaches. Always remember to use the appropriate .tsx extension for files that contain JSX syntax. This small adjustment goes a long way in ensuring that your components render correctly during testing. Now, go ahead and apply these tips to your projects, and keep coding confidently in React and TypeScript!