Warning: isMounted(…) is deprecated in plain Javascript Classes

Question

I am implementing 2 screens using react-navigation. But I got the warning below while navigating to the second page:

Warning: isMounted(...) is deprec

Answer 1

This is a problem with latest React Navigation and React Native. To silence it add:

import { YellowBox } from 'react-native';
YellowBox.ignoreWarnings(['Warning: isMounted(...) is deprecated', 'Module RCTImageLoader']);

I expect it will be fixed in React Navigation within next few weeks.

Answer 2

Use this statement in index.js:

import { YellowBox } from 'react-native';
YellowBox.ignoreWarnings(['Warning: isMounted(...) is deprecated', 'Module RCTImageLoader']);

Answer 3

The answers above didn't work for me, but adding the following to index.js did the trick:

console.ignoreYellowBox = ['Warning: isMounted(...) is deprecated'];

Or upgrade to expo 27.0.2 which basically adds the above to Expo.js. See more information here: https://forums.expo.io/t/warnings-after-upgrade-to-expo-27/9579/10

As some of the other answers stated, it's a react-native issue so hopefully it will be fixed soon there and then in the following version of Expo.

Answer 4

This is what i did for this problem for the time being:

step 1:Tap on the warning

step 2: In the yellow window click on the stack trace option in top right

step 3: Find the path where the warning has occured,ex:C:\Users\username\projectname\node_modules\react\cjs\react.development.js

step 4: Open the path in editor

step 5: Find the key word isMounted under the deprecated api's and delete the deprecated function and warning related under it.

step 6: Save and reload your app!!thats it

Answer 5

Ignoring this message is the wrong way for a good developer If we remove this problem then the memory leakage is decreased.

Answer 6

If you are using EXPO for RN development then this issue is now fixed in expo 27.0.2.

See https://forums.expo.io/t/warnings-after-upgrade-to-expo-27/9579/12