npm-installed library not working

[jivemiguel]

I ran this from the command line to add a library to my Expo app:

yarn add react-native-text-size
react-native link react-native-text-size

Then rebuilt my app. However, when I import and use in a component with:

import rnTextSize from 'react-native-text-size';
...
componentDidMount() {
 const size = rnTextSize.measure({
    text: 'Measure me baby'
 });
}

It throws this error:

TypeError: TypeError: undefined is not an object (evaluating '_reactNativeTextSize.default.measure')

Is there an Expo-related reason why a third-party npm library can’t be used? Or am I missing something about getting a third party library to show up in NativeModules?

[scootermap]

https://docs.expo.io/versions/latest/introduction/faq/#how-do-i-add-custom-native-code

Have you ejected?

[jivemiguel]

No, and that will be why. I was looking at this documentation:

https://docs.expo.io/versions/latest/react-native/native-modules-setup/

But it didn’t mention that you need to eject. I’ll get on that.

Thanks very much.