diff --git a/code_style.md b/code_style.md
index c90ad359b3..6333e8cd94 100644
--- a/code_style.md
+++ b/code_style.md
@@ -156,7 +156,7 @@ ECMAScript
   - Be careful mixing arrow functions and regular functions, eg. if one function in a promise chain is an
     arrow function, they probably all should be.
 - Apart from that, newer ES features should be used whenever the author deems them to be appropriate.
-- Flow annotations are welcome and encouraged.
+- While flow annotations are welcome and encouraged consider to migrate the JS file to TypeScript (see next section).
 
 TypeScript
 ----------