babel-preset-env: `DEBUG` option

Using targets:
{
  "chrome": "55"
}

Using modules transform: false

Using plugins:
  check-es2015-constants {}
  transform-es2015-arrow-functions {}
  transform-es2015-block-scoped-functions {}
  transform-es2015-block-scoping {}
  transform-es2015-classes {}
  transform-es2015-computed-properties {}
  transform-es2015-destructuring {}
  transform-es2015-duplicate-keys {}
  transform-es2015-for-of {}
  transform-es2015-function-name {}
  transform-es2015-literals {}
  transform-es2015-object-super {}
  transform-es2015-parameters {}
  transform-es2015-shorthand-properties {}
  transform-es2015-spread {}
  transform-es2015-sticky-regex {}
  transform-es2015-template-literals {}
  transform-es2015-typeof-symbol {}
  transform-es2015-unicode-regex {}
  transform-new-target {}
  transform-regenerator {}
  transform-exponentiation-operator {}
  transform-async-to-generator {}
  syntax-trailing-function-commas { "chrome":"55" }

Using polyfills with `entry` option:

[src/in.js] Replaced `babel-polyfill` with the following polyfills:
  es7.string.pad-start { "chrome":"55" }
  es7.string.pad-end { "chrome":"55" }
  web.timers { "chrome":"55" }
  web.immediate { "chrome":"55" }
  web.dom.iterable { "chrome":"55" }
src/in.js -> lib/in.js