JavaScript bindings for Endless Sky C++ code

JavaScript wrapper for the C++ classes in Endless Sky, compiled to JavaScript + WebAssembly by Emscripten.

npm install endless-sky-bindings

Usage examples

Use as a ES6 Module in node:

import libFactory from "endless-sky-bindings/dist/es-node.js";

(async function () {
  const esLib = await libFactory();
  console.log(new esLib.Point(1, 2));
})();

Use in a browser script tag, without a bundler:

<script type="module">
(async function() {
  const {default: esLibFactory} = await import('https://unpkg.com/endless-sky-bindings/dist/es-web.mjs?module');
  const esLib = await esLibFactory();
  esLib.GameDataBeginLoad([]); // optional
  console.log(new esLib.Point(1, 2));
})();
</script>

Use in the node REPL (shown with top-level await which is on by default in node 16, for node <16 use node --experimental-repl-await):

> const {default: libFactory} = await import('endless-sky-bindings/dist/es-node.js');
> const esLib = await libFactory();
> p = new esLib.Point(1, 2));
Point {}
> p.X();
1

Use in an Observable Notebook

Wrapped classes

See lib.cpp for which classes are wrapped. It's not hard to add more, but there are some limitations:

• only one constructor overload can be directly exposed
• int64 conversions require manual wrapping to convert to int
• I haven't figured out templates

How this works

This repository has a specific commit of Endless Sky as a submodule. A patch (patch.diff) is applied to it, mostly to make it compile with the Emscripten toolchain. This patch is based on the changes made to Endless Sky in the Endless Web fork.

These modified Endless Sky C++ files are compiled with Emscripten with bindings provided by the Emscripten embind macros in lib.cpp.

These distributed files include core Endless Sky game data but not images or sounds.

Potential Uses of this library

These aren't possible yet, but might influence design.

• npm-installable command line data parser which exactly mirrors game loading logic
• live preview of derived properties when making data file changes
• GUI ship editor that produces data files for plugin authors
• text editor tool providing autocompletion and syntax highlighting when writing data files
• "fly this ship around" widget that embeds the full game on a webpage with tweakable stats/outfits
• player assistance tools displaying game information live as it is played
• online mission editor tool
• deep linking to game situations more specific than a savefile
• hooks into game logic for customization of https://play-endless-web.com from JavaScript