Configure Rollup to bundle Axios module

1. npm install rollup-plugin-node-resolve rollup-plugin-json.

2. Add it to the plugins inside rollup.config.js

// Rollup configuration
...
plugins: [
    rollupNodeResolve({
      jsnext: true,
      preferBuiltins: true,
      browser: true
    }),
    rollupJson(),
    ...
]

** Notice the browser: true **

3. Run your build again: yarn run build

Voila!

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