Updated to expo 20, getting warning about app.json


#1

I updated to expo 20.0.1 , RN 047.1, jest-expo 0.20.0 and react-native-scripts 1.2.2.
When i run the packager I get the following warning:

Warning: Problem validating app.json: regeneratorRuntime is not defined.


#2

I am as well! Thanks


#3

can either of you share the project that this happens on?


#4

Sending you an invite now!


#5

cloned it, ran yarn, ran yarn start, worked


#6
yarn dev v0.27.5
$ yarn configure:dev && exp start -c --localhost --ios --no-minify --dev
[exp] Using project at /Users/peter/Projects/preposterous/orchard-react-native
[exp] Warning: Problem validating app.json: regeneratorRuntime is not defined.

node 7.10.1
npm 4.2.0

App still works fine, but you get the warning. I thought it was only taking place when running npm 5, but still happens on v4

Not an issue for me, just wanted to report the warning!


#7

I’m getting this warning as well on expo@20.0.0 and react-native-scripts@1.2.1, and my app crashes with the error undefined is not an object (evaluating 'regeneratorRuntime.mark').

I should include that I’m using generator functions and redux-saga in this project.


#8

This issue / comment is relevant, but I’m just not sure what to do to fix this in my CRNA app while waiting for the next expo-vendored react-native version.


#9

@peterpme I’m sorry if this is a dumb question, but which version of exp are you using?


#10

No question is dumb! v44.0.0


#11

This resolved it for me: https://github.com/expo/expo/issues/519. To be clear, if you have a generator function like function* namedGenerator() {}, you can’t use it directly as namedGenerator, you need to set it as some variable/constant first… e.g.:

const namedGeneratorFn = function* namedGenerator() {};

// This will NOT work!
// export default namedGenerator;

// This will work
export default namedGeneratorFn;

#12

Im not using this namedGenerator() { } function. But i still get this warning message. And after that I never get the build built . I always get this error: undefined