Flow: Throws error Cannot resolve module "react-redux" even tho it's installed

How to fix it

You have two options:

1. stub the dependency by hand
2. bring in flow-typed to find the dependency type file/stub it for you

I use option 2 but it is nice to know what is happening underneath

Option 1

In .flowconfig, add a directory under [libs],

...
[libs]
/type-def-libs
...

Now, create that directory at your project root and a file /type-def-libs/react-redux which contains,

declare module 'react-redux' {
  declare module.exports: any;
}

Option 2

• install flow-typed, if using yarn yarn add -D flow-typed
  • I prefer to install every locally to the project when possible
• run yarn flow-typed install
  • this will install any type definition files for modules that it finds AND it will stub any modules it doesn't find, which is similar to what we did in option 1

Why is this error happening

Flow is looking for the type definition for the module you are importing. So while the module does exist in /node_modules that module doesn't have a type definition file checked into its code.

I had the same issue as you.

I resolved it by using flow-typed

I did the following:

1. Install flow-typed globally. example: $ npm install -g flow-typed
2. Then inside your project root folder, run $ flow-typed install [email protected] • Searching for 1 libdefs... • flow-typed cache not found, fetching from GitHub... • Installing 1 libDefs... • react-redux_v5.x.x.js └> ./flow-typed/npm/react-redux_v5.x.x.js react-redux You should see this if the install was successful.
3. Then try running flow again $ npm run flow in your project. The error with react-redux will no longer be there.

Alternative solution (for some cases)

Check your .flowconfig and remove <PROJECT_ROOT>/node_modules/.* under the field [ignore] (in case you have it there).

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Thanks to @meloseven who solved it here.