buble-config-rhino

A Bublé configuration that transpiles modern JavaScript for Rhino, the Java-based JavaScript engine made by Mozilla.

Bublé is a JavaScript transpiler that transpiles modern JavaScript for legacy JavaScript runtimes that only support ES5. Mozilla Rhino is one such system.

This package provides a configuration (i.e. preset) for Bublé that can be reused across JavaScript projects targeting Rhino. It selectively enables transpilation for ES2015+ features unsupported by Rhino, while allowing supported features to be emitted as-is.

How to use

buble-config-rhino exports a single function. This function returns a configuration object that can be passed to buble.transform(), which then transpiles modern ECMAScript to a subset of ES5+ that Rhino supports:

const buble = require("buble");
const createPreset = require("buble-config-rhino");
// Note: buble-config-rhino also provides native ESM exports
// import { createPreset } from "buble-config-rhino";

const output = buble.transform(code, createPreset());

If there is a feature that you want to turn on or off, you can pass an options object to createPreset() that will override the defaults:

const output = buble.transform(
  code,
  createPreset({
    transforms: {
      arrow: true,
      dangerousTaggedTemplateString: false,
    },
  })
);

createPreset() accepts the same options object as buble.transform().

Rollup

Use @rollup/plugin-buble with this config:

// rollup.config.js
import buble from "@rollup/plugin-buble";
import createPreset from "buble-config-rhino";

export default {
  // ...
  plugins: [buble(createPreset())],
};

Webpack

Use buble-loader with this config:

// webpack.config.js
const path = require("path");
const createPreset = require("buble-config-rhino");

module.exports = {
  // ...
  module: {
    rules: [
      {
        test: /\.js$/,
        loader: "buble-loader",
        include: path.join(__dirname, "src"),
        options: createPreset(),
      },
    ],
  },
};

Transpiled language features

See index.ts for a list of enabled/disabled transforms.

Note that, unlike Babel, Bublé does not add polyfills. You must add them manually.

See also: List of ES2015+ features supported by Rhino (may be outdated)