Eliminates ProxyAdmin code duplication in ProxyAdminProject and AppProject using TypeScript Mixins

packages/lib/src/project/AppProject.ts

@@ -5,6 +5,7 @@ import isEmpty from 'lodash.isempty';
 import App from '../application/App';
 import Package from '../application/Package';
 import ProxyAdmin from '../proxy/ProxyAdmin';
+import ProxyAdminProjectMixin from './mixin/ProxyAdminProjectMixin';
 import ImplementationDirectory from '../application/ImplementationDirectory';
 import BasePackageProject from './BasePackageProject';
 import SimpleProject from './SimpleProject';
@@ -37,7 +38,7 @@ interface ExistingAddresses {
   proxyFactoryAddress?: string;
 }
 
-export default class AppProject extends BasePackageProject {
+class BaseAppProject extends BasePackageProject {
   private name: string;
   private app: App;
   public proxyAdmin: ProxyAdmin;
@@ -68,7 +69,7 @@ export default class AppProject extends BasePackageProject {
       if (!await app.hasPackage(name, version)) await app.setPackage(name, thepackage.address, version);
       const proxyAdmin: ProxyAdmin | null = proxyAdminAddress ? await ProxyAdmin.fetch(proxyAdminAddress, txParams) : null;
       const proxyFactory = ProxyFactory.tryFetch(proxyFactoryAddress, txParams);
-      const project: AppProject = new this(app, name, version, proxyAdmin, proxyFactory, txParams);
+      const project: AppProject = new AppProject(app, name, version, proxyAdmin, proxyFactory, txParams);
       project.directory = directory;
       project.package = thepackage;
       return project;
@@ -130,11 +131,6 @@ export default class AppProject extends BasePackageProject {
   public getAdminAddress(): Promise<string> {
     return new Promise((resolve) => resolve(this.proxyAdmin ? this.proxyAdmin.address : null));
   }
-
-  public async transferAdminOwnership(newAdminOwner: string): Promise<void> {
-    await this.proxyAdmin.transferOwnership(newAdminOwner);
-  }
-
   public getApp(): App {
     return this.app;
   }
@@ -237,10 +233,6 @@ export default class AppProject extends BasePackageProject {
     return this.proxyAdmin.upgradeProxy(proxyAddress, implementationAddress, contract, initMethod, initArgs);
   }
 
-  public async changeProxyAdmin(proxyAddress: string, newAdmin: string): Promise<void> {
-    return this.proxyAdmin.changeProxyAdmin(proxyAddress, newAdmin);
-  }
-
   public async getDependencyPackage(name: string): Promise<Package> {
     const packageInfo = await this.app.getPackage(name);
     return packageInfo.package;
@@ -275,3 +267,6 @@ export default class AppProject extends BasePackageProject {
     }
   }
 }
+// Mixings produce value but not type
+// We have to export full class with type & callable
+export default class AppProject extends ProxyAdminProjectMixin(BaseAppProject) {};

packages/lib/src/project/ProxyAdminProject.ts

@@ -5,16 +5,17 @@ import BaseSimpleProject from './BaseSimpleProject';
 import { ContractInterface } from './AppProject';
 import Contract from '../artifacts/Contract';
 import ProxyFactory from '../proxy/ProxyFactory';
+import ProxyAdminProjectMixin from './mixin/ProxyAdminProjectMixin';
 
 const log: Logger = new Logger('ProxyAdminProject');
 
-export default class ProxyAdminProject extends BaseSimpleProject {
+class BaseProxyAdminProject extends BaseSimpleProject {
   public proxyAdmin: ProxyAdmin;
 
-  public static async fetch(name: string = 'main', txParams: any = {}, proxyAdminAddress?: string, proxyFactoryAddress?: string) {
+  public static async fetch(name: string = 'main', txParams: any = {}, proxyAdminAddress?: string, proxyFactoryAddress?: string): Promise<ProxyAdminProject> {
     const proxyAdmin = proxyAdminAddress ? await ProxyAdmin.fetch(proxyAdminAddress, txParams) : null;
     const proxyFactory = proxyFactoryAddress ? await ProxyFactory.fetch(proxyFactoryAddress, txParams) : null;
-    return new this(name, proxyAdmin, proxyFactory, txParams);
+    return new ProxyAdminProject(name, proxyAdmin, proxyFactory, txParams);
   }
 
   constructor(name: string = 'main', proxyAdmin: ProxyAdmin, proxyFactory?: ProxyFactory, txParams: any = {}) {
@@ -40,23 +41,18 @@ export default class ProxyAdminProject extends BaseSimpleProject {
     return contract.at(pAddress);
   }
 
-  public async changeProxyAdmin(proxyAddress: string, newAdmin: string): Promise<void> {
-    await this.proxyAdmin.changeProxyAdmin(proxyAddress, newAdmin);
-    log.info(`Proxy ${proxyAddress} admin changed to ${newAdmin}`);
-  }
-
   public getAdminAddress(): Promise<string> {
     return new Promise((resolve) => resolve(this.proxyAdmin ? this.proxyAdmin.address : null));
   }
 
-  public async transferAdminOwnership(newAdminOwner: string): Promise<void> {
-    await this.proxyAdmin.transferOwnership(newAdminOwner);
-  }
-
   public async ensureProxyAdmin(): Promise<ProxyAdmin> {
     if (!this.proxyAdmin) {
       this.proxyAdmin = await ProxyAdmin.deploy(this.txParams);
     }
     return this.proxyAdmin;
   }
 }
+
+// Mixings produce value but not type
+// We have to export full class with type & callable
+export default class ProxyAdminProject extends ProxyAdminProjectMixin(BaseProxyAdminProject) {};

packages/lib/src/project/mixin/ProxyAdminProjectMixin.ts

@@ -0,0 +1,21 @@
+import Constructable, { AbstractType, GetMixinType } from '../../utils/Mixin';
+import ProxyAdmin from '../../proxy/ProxyAdmin';
+
+// A mixin that adds ProxyAdmin field and related ProxyAdminProject methods
+// Intented to as a building block for Project class
+// Can't extend contructor at that moment due to TypeScript limitations https://github.com/Microsoft/TypeScript/issues/14126
+function ProxyAdminProjectMixin<T extends Constructable>(Base: T) {
+  return class extends Base {
+    public proxyAdmin: ProxyAdmin;
+
+    public async transferAdminOwnership(newAdminOwner: string): Promise<void> {
+      await this.proxyAdmin.transferOwnership(newAdminOwner);
+    }
+
+    public async changeProxyAdmin(proxyAddress: string, newAdmin: string): Promise<void> {
+      return this.proxyAdmin.changeProxyAdmin(proxyAddress, newAdmin);
+    }
+  };
+}
+
+export default ProxyAdminProjectMixin;

packages/lib/src/utils/Mixin.ts

@@ -0,0 +1,7 @@
+type Constructable<T = {}> = new (...args: any[]) => T;
+export type Callable<T = any> = (...args: any[]) => T;
+export type AbstractType<T = {}> = Function & { prototype: T };
+
+export type GetMixinType<T extends Callable> = InstanceType<ReturnType<T>>;
+
+export default Constructable;