@babel/preset-env: `DEBUG` option

Using targets:
{
  "chrome": "52",
  "firefox": "50",
  "ie": "11"
}

Using modules transform: auto

Using plugins:
  transform-template-literals { "ie":"11" }
  transform-literals { "firefox":"50", "ie":"11" }
  transform-function-name { "firefox":"50", "ie":"11" }
  transform-arrow-functions { "ie":"11" }
  transform-classes { "ie":"11" }
  transform-object-super { "ie":"11" }
  transform-shorthand-properties { "ie":"11" }
  transform-duplicate-keys { "ie":"11" }
  transform-computed-properties { "ie":"11" }
  transform-for-of { "firefox":"50", "ie":"11" }
  transform-sticky-regex { "ie":"11" }
  transform-dotall-regex { "chrome":"52", "firefox":"50", "ie":"11" }
  transform-unicode-regex { "ie":"11" }
  transform-spread { "ie":"11" }
  transform-parameters { "firefox":"50", "ie":"11" }
  transform-destructuring { "firefox":"50", "ie":"11" }
  transform-block-scoping { "firefox":"50", "ie":"11" }
  transform-typeof-symbol { "ie":"11" }
  transform-new-target { "ie":"11" }
  transform-regenerator { "firefox":"50", "ie":"11" }
  transform-exponentiation-operator { "firefox":"50", "ie":"11" }
  transform-async-to-generator { "chrome":"52", "firefox":"50", "ie":"11" }
  proposal-async-generator-functions { "chrome":"52", "firefox":"50", "ie":"11" }
  proposal-object-rest-spread { "chrome":"52", "firefox":"50", "ie":"11" }
  proposal-unicode-property-regex { "chrome":"52", "firefox":"50", "ie":"11" }
  proposal-json-strings { "chrome":"52", "firefox":"50", "ie":"11" }
  proposal-optional-catch-binding { "chrome":"52", "firefox":"50", "ie":"11" }
  transform-named-capturing-groups-regex { "chrome":"52", "firefox":"50", "ie":"11" }

Using polyfills with `usage` option:

[<CWD>/src/in.js] Added following core-js polyfills:
  es6.object.to-string { "chrome":"52", "firefox":"50", "ie":"11" }
  es6.promise { "ie":"11" }
  es6.map { "firefox":"50", "ie":"11" }
  es6.string.iterator { "ie":"11" }
  es6.array.iterator { "ie":"11" }
  web.dom.iterable { "chrome":"52", "firefox":"50", "ie":"11" }

[<CWD>/src/in2.js] Added following core-js polyfill:
  web.dom.iterable { "chrome":"52", "firefox":"50", "ie":"11" }

[<CWD>/src/in2.js] Based on your code and targets, added regenerator-runtime.
Successfully compiled 2 files with Babel.