It's pretty straight forward to use JSX outside of React. If you're using Babel you can simply add

    /** @jsx ExampleDOM */

As the first line in your Javascript source file. This indicates to the transpiler to convert statements of the form

    <example name="Wesley" age={15}>
        <Message text="hello"/>
        <Message text="world"/>
    </example>

into

    ExampleDOM('example', { name: 'Wesley', age: 15 },
        ExampleDOM(Message, { text: 'hello'}),
        ExampleDOM(Message, { text: 'world })
    )

where you implement ExampleDom as

    function ExampleDOM(element_or_component, attributes, ...children) {


    }

Note that because 'example' starts with a lowercase character, it is transpiled into a string first-argument to the ExampleDOM function. If it starts with an Uppercase letter (i.e. 'Message' above) it is interpreted as an in-scope Javascript variable.

We've had really good results using JSX outside of the core react library. For example, we've built a "React.js for Excel" that lets us easily create rich Excel workbooks:

      <worksheet
        clear
        protect
        flow="column"
        name={`Bespoke - ${network.shortname} - WACC`}
        tabColor={theme.bespokeBlue}
        displayGridlines={false}
        style={worksheetStyle}>
        <PageLayout
          title={`${network.name} Cost-of-Capital Worksheet`}
          lastUpdated={new Date()}>
          <UpdatedWACCEstimates network={network} determination={determination}/>
          <WACCForecast network={network} forecast={forecast}/>
        </PageLayout>
      </worksheet>

Which looks a lot like React.js and behaves almost exactly the same, but it's targeting the Excel COM Object model rather than the HTML DOM.