I've been using Immutable.js for my react app and I'm loving it. Facebook also released Flow. Flow would let me do very cool things like pile time validation of prop types. The problem is that my props are generally Immutable objects. Is there a good way to use Immutable.js and Flow together?

Given an Immutable.js object parameter can I use Flow to somehow specify the type of the object it should be wrapping? Within that object I might have strings, numbers, booleans, and more importantly other Immutable.js objects.

I've been using Immutable.js for my react app and I'm loving it. Facebook also released Flow. Flow would let me do very cool things like pile time validation of prop types. The problem is that my props are generally Immutable objects. Is there a good way to use Immutable.js and Flow together?

Given an Immutable.js object parameter can I use Flow to somehow specify the type of the object it should be wrapping? Within that object I might have strings, numbers, booleans, and more importantly other Immutable.js objects.

• javascript
• reactjs
• flowtype

• Maybe you can use accessors to statically annotate that dynamic part of the Immutable.js. – user217782 Commented Dec 10, 2014 at 12:47
• Do you mean wrap an immutable object with a custom object that provides annotated accessors? – Kilamanjaro Kablam Commented Dec 10, 2014 at 17:34
• @brandon-tilley I hesitated to use the flowtype tag because there is a pletely unrelated project that has to do with typography called FlowType.JS. – Kilamanjaro Kablam Commented Dec 11, 2014 at 4:10
• Any luck on this @KilamanjaroKablam ? – Riley Lark Commented May 29, 2015 at 1:10
• 1 Flow more about JS types. You can use npmjs./package/react-immutable-proptypes for check prop types. It works for me. – Dmitry Manannikov Commented Jun 7, 2015 at 20:30

2 Answers 2

At the time of writing, you can use the two together by grabbing the interface file from here:

https://github./facebook/immutable-js/blob/master/type-definitions/immutable.js.flow

1. Create a directory within your project, for example interfaces.
2. Create a .flowconfig if it doesn't exist, and add the following lines

.flowconfig

[libs]
interfaces/

This will look in the ./interfaces/ directory for Flow definitions.

Although linking to a resource is frowned upon on SO, it that case it makes sense as that will be the most up to date (I'm assuming FB will keep it update as they update the core library)

Edited to add that flowtypes have been added since most recent major version.

Original answer:

Looks like integration between Flow and Immutable.js is in development but not yet plete.