[React Flow] Up and Running with Facebook Flow for Typed JavaScript

Install:

npm i -D flow-bin
npm i -g flow-bin

Init:

flow init

Script:

"typecheck": "flow src"

Check the src folder.

Add mark to the file which you want to check:

/*@flow */

function to be checked:

function add(x: number, y: number){

    return x + y;

}

add(1, '2');

When the flow runs, it will report the error because '2' we passed in is a string not a number.

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Notic: Flow only works with Mac and Linux.

See more: Link