Better console.log debugging

DEBUG.js

self.DEBUG_ON = true;
function DEBUG(...args) {
  if (!DEBUG_ON) { return; }
  const stack = (new Error().stack).match(/\s+at .*\s+at ([^\(]+)/);
  const caller = stack && stack[1] ? stack[1].replace(/\s+$/, '') : 'top_level';
  (console.debug || console.log)(`[DEBUG@(${caller})]:`, ...args);
}
Object.defineProperty(Object.prototype, 'DEBUG', {
  value: function DEBUG_PIPE(msg, ...args) {
           DEBUG(msg, this, ...args);
           return this;
         },
  enumerable: false
});