Add method to get an strategy instance from authenticator

Closes #309

src/index.test.ts

@@ -50,4 +50,11 @@ describe(Authenticator.name, () => {
 			await auth.authenticate("mock", new Request("http://remix.auth/test")),
 		).toEqual({ id: 1 });
 	});
+
+	test("#get", () => {
+		let auth = new Authenticator();
+		let strategy = new MockStrategy(async () => ({ id: 1 }));
+		expect(auth.use(strategy)).toBe(auth);
+		expect(auth.get("mock")).toBe(strategy);
+	});
 });

src/index.ts

@@ -41,20 +41,26 @@ export class Authenticator<User = unknown> {
 		return this;
 	}
 
+	/**
+	 * Call this method with the name of a strategy you want to get.
+	 * It returns the Strategy instance or null if the strategy is not found.
+	 * @param name
+	 * @returns
+	 */
+	get(name: string) {
+		return this.strategies.get(name) ?? null;
+	}
+
 	/**
 	 * Call this to authenticate a request using some strategy. You pass the name
 	 * of the strategy you want to use and the request to authenticate.
 	 * @example
 	 * async function action({ request }: ActionFunctionArgs) {
-	 *   let user = await auth.authenticate("some", request);
-	 * };
-	 * @example
-	 * async function action({ request, context }: ActionFunctionArgs) {
-	 *   let user = await auth.authenticate("some", request, { context });
+	 *   let user = await auth.authenticate("strategy-name", request);
 	 * };
 	 */
 	authenticate(strategy: string, request: Request): Promise<User> {
-		let instance = this.strategies.get(strategy);
+		let instance = this.get(strategy);
 		if (!instance) throw new ReferenceError(`Strategy ${strategy} not found.`);
 		return instance.authenticate(new Request(request.url, request));
 	}