Promises swallow syntax errors

[sryze]

Environment

  React Native Environment Info:
    System:
      OS: macOS High Sierra 10.13.6
    Binaries:
      Node: 11.0.0 - /usr/local/bin/node
      npm: 6.4.1 - /usr/local/bin/npm
      Watchman: 4.9.0 - /usr/local/bin/watchman
    SDKs:
      iOS SDK:
        Platforms: iOS 11.4, macOS 10.13, tvOS 11.4, watchOS 4.3
      Android SDK:
        API Levels: 17, 18, 19, 21, 22, 23, 24, 25, 26, 27, 28
        Build Tools: 23.0.1, 25.0.0, 25.0.1, 26.0.1, 26.0.3, 27.0.3, 28.0.3
        System Images: android-28 | Google Play Intel x86 Atom
    IDEs:
      Android Studio: 3.2 AI-181.5540.7.32.5056338
      Xcode: 9.4.1/9F2000 - /usr/bin/xcodebuild
    npmPackages:
      react: ^16.6.1 => 16.6.1
      react-native: 0.57.2 => 0.57.2
    npmGlobalPackages:
      create-react-native-app: 2.0.2
      react-native-cli: 2.0.1

Description

.then() blocks and await should not swallow programming errors like syntax errors or undefined variables, they should cause a red box to appear and an error to be logged like with synchronous code. This can make it easier to find and debug errors in asynchronous code.

Reproducible Demo

promise.then(() => {
    console.log(someUndefinedVar) // oops
}).catch(error => {
    // error is passed here
})