Set react native global variable from Xcode

Question

I saw that there is the __DEV__ variable, and I would like to add my own, say __USE_THIS__. Then way I set this is when the Xcode project is building, but I don't know how to pass that to the js part. Can I use the bundle script and pass it there somehow? When is the __DEV__ set, and how?

thi looks somehow related: github.com/luggit/react-native-config — Ivan Chernykh
– Ivan Chernykh, Commented Feb 23, 2017 at 19:55
I want to pass something like __USE_THIS__ = true, and in that case the js will do something different than if it was false (by default). — pvinis
– pvinis, Commented Feb 23, 2017 at 22:51
I checked the react-native-config, but that uses .env, and that means I will pass those everywhere. I would be happy with a simpler way of just passing something one-way from xcode to js. — pvinis
– pvinis, Commented Feb 23, 2017 at 22:53

mien · Accepted Answer · 2017-04-28 10:46:38Z

5

You could have Target/Scheme specific variables exposed to javascript by writing them to a file during Build Phase and then import them in the javascript.

1) Add the following to "Bundle React Native code and images" under "Build Phase" for your target:

export NODE_BINARY=node
echo '{"target": "MyTarget"}' > ../build-info.json
../node_modules/react-native/packager/react-native-xcode.sh

Example screenshot from xcode

2) Import them in the javascript, for example in index.ios.js

import buildInfo from '../../build-info.json'
console.log(buildInfo.target)

It should also be possible to write a file to $PROJECT_ROOT/.env and use it through something like react-native-config instead if you prefer

answered Apr 28, 2017 at 10:46

mien

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