Render React template from Nashorn

This is just an experiment tracking the feasibility of using v.latest React in Nashorn.

Recent Spring Developer presentation: isomorphic-templating-with-spring-boot-nashorn-and-react

React 16.1.x

0.13.x leaned on JSX Transformer to perform standalone JSX translation; this was removed in current React versions. A BabelJs environment is needed to compile JSX. However, BabelJs also needs NodeJs environment, so use a babel-standalone that bundles all required modules.

Now in 4.2.0.RELEASE

Jira SPR-12266 Spring Framework SPR-12266

Use jdk-8u72-ea or higher. https://jdk8.java.net/download.html

Early access fix for: Method code too large in Babel - https://bugs.openjdk.java.net/browse/JDK-8135190

Note:- this is also the case with Typescript microsoft/TypeScript#1789

Spring Boot with ReactJs templates with Nashorn and Kotlin 1.2.x

React 16.1.x requires BabelJs environment to compile JSX BabelJs requires nodejs api dependencies.

However, a stand-alone build of Babel for use in non-Node.js environments used as https://babeljs.io/docs/usage/browser/ now removed. https://github.com/Daniel15/babel-standalone

The package create-react-class is used as Java8 Nashorn is ECMAScript 5.x as per https://reactjs.org/docs/react-without-es6.html

Nashorn Extensions - allow map support

global = {};
console = {};
console.debug = print;
console.warn = print;
console.log = print;
console.error = print;

function render(template, model) {
    var data = {};
    for (var k in model) {
        if (model[k] instanceof Java.type("java.lang.Iterable")) {
             data[k] = Java.from(model[k]);
        } else {
            data[k] = model[k];
        }
    }
    var element = React.createElement(eval(template), data);
    return ReactDOMServer.renderToStaticMarkup(element);
}

function renderJsx(template, model) {
    var jsTemplate = Babel.transform(template, { presets: ['react'] }).code;
    return render(jsTemplate, model);
}

Notes on Spring Boot

Test with JDK

./gradlew test

Application

./gradlew bootRun

Route

http://localhost:8080/about.html

Rendered from

https://github.com/griffio/spring-boot-web-nashorn/blob/master/src/main/resources/templates/about.jsx

==============

Kotlin 1.2.x

kotlin_version=1.2.21

basic gradle (4.x) build template for Java 8