fix resolvers in prod (#309)

Author: YousefED

packages/engine/src/resolvers/ExternalModuleResolver.ts

@@ -1,4 +1,6 @@
 export abstract class ExternalModuleResolver {
+  public abstract readonly name: string;
+
   public abstract getURLForModule(
     moduleName: string,
     parent: string

packages/engine/src/resolvers/ImportShimResolver.ts

@@ -53,23 +53,18 @@ export class ImportShimResolver {
     for (let resolver of this.resolvers) {
       try {
         const module = await this.importShim(
-          "use$" + resolver.constructor.name + "$" + moduleName
-        );
-        console.log(
-          "loaded module",
-          moduleName,
-          "using",
-          resolver.constructor.name
+          "use$" + resolver.name + "$" + moduleName
         );
+        console.log("loaded module", moduleName, "using", resolver.name);
         return {
           module,
           dispose: () => {},
         };
       } catch (e) {
-        console.error("failed loading module", resolver.constructor.name, e);
+        console.error("failed loading module", resolver.name, e);
       }
     }
-    throw new Error("couldn't resolve module" + moduleName);
+    throw new Error("couldn't resolve module " + moduleName);
   }
 
   /**
@@ -213,7 +208,7 @@ export class ImportShimResolver {
       if (parts.length !== 3) {
         throw new Error("expected resolver name in import" + id);
       }
-      resolver = this.resolvers.find((r) => r.constructor.name === parts[1])!;
+      resolver = this.resolvers.find((r) => r.name === parts[1])!;
       id = parts[2];
     } else {
       if (!parent) {

packages/engine/src/resolvers/cdns/ESMshResolver.ts

@@ -1,6 +1,8 @@
 import { ExternalModuleResolver } from "../ExternalModuleResolver";
 
 export class ESMshResolver extends ExternalModuleResolver {
+  public readonly name = "esm.sh";
+
   public async getModuleInfoFromURL(url: string) {
     // https://cdn.esm.sh/v66/@tldraw/[email protected]/es2021/core.js
 

packages/engine/src/resolvers/cdns/JSPMResolver.ts

@@ -1,6 +1,8 @@
 import { ExternalModuleResolver } from "../ExternalModuleResolver";
 
 export class JSPMResolver extends ExternalModuleResolver {
+  public readonly name = "jspm";
+
   public async getModuleInfoFromURL(url: string) {
     // TODO: should also pass version identifier (@xx)
 

packages/engine/src/resolvers/cdns/SkypackResolver.ts

@@ -1,6 +1,8 @@
 import { ExternalModuleResolver } from "../ExternalModuleResolver";
 
 export class SkypackResolver extends ExternalModuleResolver {
+  public readonly name = "skypack";
+
   public async getModuleInfoFromURL(url: string) {
     // skypack, e.g.: https://cdn.skypack.dev/-/[email protected]/dist=es2020,mode=imports/unoptimized/dist/index.cjs.js
     // TODO: should also pass version identifier (@xx)