How to install flow type correctly for react [email protected]+?

Question

I've googled many sites but cannot found a tutorial that actually works for react-native + flow type.

There was flow installation guide from [email protected] document, but it's gone in [email protected].

However, it comes up again in Running Tests and Contributing, I tested to run npm run flow but not working, and yet it doesn't say how to make it works. It's possibly been a missing part inside of react-native documentation.

What I need is to run flow correctly with react-native. Auto-check flow every time I reload the page with ⌘R would be the best.

Answer 1

I just finished covering half of our project by flow and we use RN 0.44.0.

The tricky part is: do you also want to know errors inside node_modules, someone says those errors are helpful.

Anyway, I disable the error in node_modules, and here is my .flowconfig:

[ignore]

<PROJECT_ROOT>/node_modules/.*
<PROJECT_ROOT>/flowLibs.js
.....
[include]

[libs]
./flowLibs.js
.....
[lints]
[options]

You should install flow first if you not setup correctly,

npm install --save-dev flow-bin

and also run this in you project root after install:

npm run flow init

If npm run flow init does not work, just add "flow": "flow" in npm scripts.

After init, put my .flowconfig in your project .flowconfig file.

Then create a js file flowLibs.js and if npm run flow check cause your any error like Module_Name. Required module not found

Write down code in flowLibs.js:

declare module 'Module_Name' {  declare var exports: any;  };

After that, you should be good to go with you project now.

BTW, don't forget add //@flow on the top of the file which you want to check type.