To extract localization messages from a React app, you'll first need to identify the localization library that the app is using. This is because the extraction process is tightly coupled with the specific library being used. In most cases, the library will have its own set of tools or guidelines for extracting messages.
For example, popular libraries like react-intl and react-i18next have their own recommended ways of extracting localization messages. You can check their documentation to see what they suggest. Generally, these libraries provide tools or APIs that allow you to mark text as translatable in your React components, and then extract those marked messages into a separate file or set of files.
Once you've identified the library being used and have reviewed its documentation, you can proceed with the extraction process. Typically, you'll need to run a command or set up a configuration file that tells the library how to extract the messages from your React code. The specifics of this process will depend on the library and its tools, so it's important to consult the documentation and follow the recommended steps.