Safari/Babel/Webpack Const declarations are not supported in strict mode - safari

Question

Safari is failing to load my React app with this line:
Const declarations are not supported in strict mode.
When I look at the line that's failing I'm seeing:
const Crypto = __webpack_require__(624)
This isn't something in my app so it must be injected by Webpack or another dependency.
Shouldn't Babel replace const with var?
Babel Dependencies
"babel": "~6.1.0",
"babel-core": "~6.2.0",
"babel-loader": "~6.2.0",
"babel-plugin-transform-runtime": "~6.1.0",
"babel-polyfill": "~6.2.0",
"babel-preset-es2015": "~6.1.0",
"babel-preset-react": "~6.1.0",
"babel-preset-stage-0": "~6.1.0",
"babel-runtime": "~6.2.0"
Babel Loader Config
{
test: /\.js|\.jsx$/,
exclude: /node_modules/,
loader: 'babel-loader',
query: {
cacheDirectory: true,
plugins: ['transform-runtime'],
presets: ['es2015', 'react', 'stage-0']
}
}
NOTE My app does work in Chrome.

Answer 1

You've excluded "node_modules" in babel-loader settings, so it doesn't process your external dependencies. This package you depend on probably is not tested for in-browser usage.
And, btw, babel won't replace your consts anyway unless you use "transform-es2015-block-scoping" plugin.
http://babeljs.io/docs/plugins/transform-es2015-block-scoping/
It's not included in "es2015" preset. There you have only "check-es2015-constants" plugin which just checks and validates const declarations.
The plugin which transforms consts into vars is called "transform-es2015-block-scoping" and it's included in "es2015" preset.