How to transpile entire vendor.js to ES5 (for IE11)

[mesqueeb]

I’m having difficulty making my app (which uses some dependencies like Firebase) work on IE11.

vendor.js seems to keep including ES6 code which can’t be read on IE11.

This is my setup:

In build.config.js

• supportIE: true,
• transpileDependencies: [/.*/],

In babel.config I have:

module.exports = {
  presets: [['@babel/preset-env']],
  plugins: ['@babel/plugin-transform-runtime']
}

But when looking in the built dist/vendor.xxxx.js file, I still find things like getOwnPropertySymbols which is not supported on IE11…

Any advice much appreciated!