formatWebpackMessage = (obj) => {
    return obj.message.trim();
  }
@fileoverview A 'build' script for Blockly extension packages.
This script:
  - Uses webpack to build the src directory in development mode if no
  additional arguments are passed.
  - Uses webpack to build the src directory in production mode if
  ``blockly-scripts build prod`` is called.
@author samelh@google.com (Sam El-Husseini)