JSX files extension

Context

In some cases, people use .js extension with files containing JSX syntax.

As of today, JSX syntax is not valid JavaScript, and using .js over .jsx breaks many tools that use .jsx files in order to switch the parsers to support JSX. In the best case, the tools allow you to configure the default parser for the files, but that is rarely done in services where they do basic parsing or relying on extensions in order to swap the parsers.

Resolution

• You MUST use .jsx file extension when the file contains JSX.