Unable to build react-native app on Android device :failed to find target with hash string 'android-23'

• Find android sdk location.(e.g /Users/username/Library/Android/sdk or /usr/local/opt/android-sdk or /Applications/ADT/sdk)

• Open shell config file that it depends on what shell you're using. ~/.bash_profile or ~/.bashrc or ~/.zshrc.

• Edit or add the following lines to shell config file:

$ export ANDROID_HOME=`YOUR_ANDROID_SDK_PATH` 
$ export PATH=$PATH:$ANDROID_HOME/tools:$ANDROID_HOME/platform-tools

• Restart the terminal and run again.

Update

Check in official website

References

• Setting ANDROID_HOME enviromental variable on Mac OS X

• React Native : target with hash string 'android-X' not found