fix: load RDKit locally from plugin folder, no internet needed

Replace CDN script injection with Node.js require() via eval to prevent
esbuild bundling. RDKit_minimal.js and RDKit_minimal.wasm are copied
next to main.js during build and loaded at runtime using __dirname.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: mikolajrura

esbuild.config.mjs

@@ -2,6 +2,10 @@ import esbuild from "esbuild";
 import process from "process";
 import builtins from "builtin-modules";
 import { copyFileSync } from "fs";
+import { resolve, dirname } from "path";
+import { fileURLToPath } from "url";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
 
 const banner = `/*
 THIS IS A GENERATED/BUNDLED FILE BY ESBUILD
@@ -11,6 +15,8 @@ if you want to view the source, please visit the github repository of this plugi
 
 const prod = process.argv[2] === "production";
 
+const rdkitSrc = resolve(__dirname, "node_modules/@rdkit/rdkit/dist");
+
 const context = await esbuild.context({
   banner: { js: banner },
   entryPoints: ["src/main.ts"],
@@ -37,11 +43,22 @@ const context = await esbuild.context({
   sourcemap: prod ? false : "inline",
   treeShaking: true,
   outfile: "main.js",
+  define: {
+    // Make __dirname available inside the bundle (plugin folder at runtime)
+    "__dirname": "__dirname",
+  },
 });
 
 if (prod) {
   await context.rebuild();
+  // Copy RDKit runtime files next to main.js
+  copyFileSync(`${rdkitSrc}/RDKit_minimal.js`, "RDKit_minimal.js");
+  copyFileSync(`${rdkitSrc}/RDKit_minimal.wasm`, "RDKit_minimal.wasm");
+  console.log("Copied RDKit_minimal.js and RDKit_minimal.wasm");
   process.exit(0);
 } else {
+  // Dev mode: also copy so hot reload works
+  copyFileSync(`${rdkitSrc}/RDKit_minimal.js`, "RDKit_minimal.js");
+  copyFileSync(`${rdkitSrc}/RDKit_minimal.wasm`, "RDKit_minimal.wasm");
   await context.watch();
 }

src/rdkit-loader.ts

@@ -1,12 +1,5 @@
-// Singleton RDKit WASM module loader.
-// RDKit is heavy (~10MB WASM), load once and reuse.
-
-declare global {
-  interface Window {
-    initRDKitModule: () => Promise<RDKitModule>;
-    RDKit: RDKitModule | null;
-  }
-}
+// Load RDKit WASM from the local plugin directory (no internet needed).
+// RDKit_minimal.js and RDKit_minimal.wasm must sit next to main.js.
 
 export interface RDKitMol {
   get_svg(): string;
@@ -18,33 +11,26 @@ export interface RDKitMol {
 
 export interface RDKitModule {
   get_mol(smiles: string): RDKitMol;
-  get_mol_from_smiles(smiles: string): RDKitMol;
   version(): string;
 }
 
 let rdkitPromise: Promise<RDKitModule> | null = null;
 
-export async function loadRDKit(): Promise<RDKitModule> {
+export function loadRDKit(): Promise<RDKitModule> {
   if (rdkitPromise) return rdkitPromise;
 
-  rdkitPromise = new Promise((resolve, reject) => {
-    // RDKit bundles a self-contained WASM init function.
-    // We load it from the CDN since bundling WASM into Obsidian plugins is complex.
-    const script = document.createElement("script");
-    script.src =
-      "https://unpkg.com/@rdkit/rdkit/Code/MinimalLib/dist/RDKit_minimal.js";
-    script.onload = async () => {
-      try {
-        const mod = await (window as any).initRDKitModule();
-        (window as any).RDKit = mod;
-        resolve(mod);
-      } catch (e) {
-        reject(e);
-      }
-    };
-    script.onerror = () => reject(new Error("Failed to load RDKit script"));
-    document.head.appendChild(script);
-  });
+  rdkitPromise = (async () => {
+    // Use Node.js require (available in Electron/Obsidian).
+    // eval('require') prevents esbuild from trying to bundle the dynamic path.
+    // __dirname points to the plugin folder where RDKit_minimal.js lives.
+    const nodeRequire = eval("require") as NodeRequire;
+    const path = nodeRequire("path") as typeof import("path");
+    const rdkitJsPath = path.join(__dirname, "RDKit_minimal.js");
+    const initRDKitModule = nodeRequire(rdkitJsPath) as (
+      opts?: object
+    ) => Promise<RDKitModule>;
+    return await initRDKitModule();
+  })();
 
   return rdkitPromise;
 }