React auto render

index.js

import React from 'react'
import { render } from 'react-dom'
import Foo from './components/foo'

const components = {
  foo: Foo
}

Object.keys(components)
  .map(name => {
    const Component = components[name]
    const className = `.js-component-${name}`
    const targets = document.querySelectorAll(className)

    ;[ ...targets ].forEach(target => {
      render(<Component />, target)
    })
  })