xjs/xjs.js

// xjs.js (development loader)
// - Dev/test: lightweight loader that imports source files (animal.js + layer.js)
// - Production: use the bundled output from `go run main.go build` (defaults to dist/xjs.js)
;(function (global) {
  'use strict';

  const g = global || (typeof window !== 'undefined' ? window : globalThis);
  const doc = (typeof document !== 'undefined') ? document : null;
  if (!doc) return;

  // Avoid double-loading
  if (g.xjs && g.Layer) return;

  const current = doc.currentScript;
  const base = (() => {
    try {
      const u = new URL(current && current.src ? current.src : 'xjs.js', location.href);
      return u.href.replace(/[^/]*$/, ''); // directory of xjs.js
    } catch {
      return '';
    }
  })();

  const loadScript = (src) => new Promise((resolve, reject) => {
    const s = doc.createElement('script');
    s.src = src;
    s.async = false; // preserve execution order
    s.onload = () => resolve();
    s.onerror = () => reject(new Error('Failed to load: ' + src));
    (doc.head || doc.documentElement).appendChild(s);
  });

  const ensureGlobals = () => {
    try {
      if (g.animal && !g.xjs) g.xjs = g.animal;
      // Optional: export `$` only when explicitly requested
      if (g.XJS_GLOBAL_DOLLAR && !g.$ && g.xjs) g.$ = g.xjs;
    } catch {}
  };

  (async () => {
    // Load animal first so xjs alias is available before layer tries to query it
    if (!g.animal) await loadScript(base + 'animal.js');
    ensureGlobals();

    if (!g.Layer) await loadScript(base + 'layer.js');
    ensureGlobals();
  })().catch((err) => {
    try { console.error('[xjs.dev] load failed', err); } catch {}
  });
})(typeof window !== 'undefined' ? window : globalThis);