Confusing error message when Xcode wants to install extra components

Environment

info Fetching system and libraries information...
System:
    OS: macOS Mojave 10.14.4
    CPU: (8) x64 Intel(R) Core(TM) i7-6920HQ CPU @ 2.90GHz
    Memory: 1.40 GB / 16.00 GB
    Shell: 2.6.0 - /usr/local/bin/fish
  Binaries:
    Node: 8.10.0 - ~/.nvm/versions/node/v8.10.0/bin/node
    Yarn: Using globally installed version of Yarn
1.12.1 - /opt/facebook/bin/yarn
    npm: 6.4.1 - ~/.nvm/versions/node/v8.10.0/bin/npm
    Watchman: 4.9.4 - /opt/facebook/bin/watchman
  SDKs:
    iOS SDK:
      Platforms: iOS 12.2, macOS 10.14, tvOS 12.2, watchOS 5.2
  IDEs:
    Android Studio: 3.5 AI-191.8026.42.35.5791312
    Xcode: 10.2.1/10E1001 - /usr/bin/xcodebuild
  npmPackages:
    react: 16.9.0 => 16.9.0 
    react-native: 0.61.2 => 0.61.2

Description

Tried to run yarn ios. Got this:

The actual problem was that when I started Xcode, it asked to install “missing components”.

Reproducible Demo

I suppose, run any projects when Xcode has “missing components”.

So What?

If we can detect this particular problem, we can show a better message than “could not parse JSON”. Ideally we should launch the command that prompts to install those Xcode “missing components” automatically.

[rickhanlonii]

Thanks @iansu, @SBinLondon is going to tackle this!

[gaearon]

It was an existing machine. Maybe I did a system update or something.