Node js and react js

[AmandaCherry]

fs is a module implemented by node.js which is not provided by javascript itself. Maybe other environments provide fs as well, but react is just a module like fs, rather than another environment, so it can not provide extra module

Another thing, react code run in browser, where you expect fs refer to? Read every user's file system?

If you want to read your local csv file. You can use some bundler like Webpack which can bundle csv file into your output Javascript file. If reading local csv is what you want, you can do some thing like

const csv =require('/path/to/csv')