add a decorator function

README.md

@@ -23,6 +23,20 @@ import { retry } from 'ts-retry-promise';
 const result = await retry(() => Promise.resolve(1), {retries: 3});
 ```
 
+### Usage as a decorator
+
+You can decorate an exisiting function like this:
+
+```typescript
+import { retryDecorator } from 'ts-retry-promise';
+
+const asyncFunction = async (s: String) => s;
+
+const decorated = retryDecorator(asyncFunction, {timeout: 1});
+
+const result : Promise<string> = decorated("1");
+```
+
 ## Interface
 
 ```typescript

src/retry-promise.ts

@@ -46,6 +46,10 @@ export async function retry<T>(f: () => Promise<T>, config?: Partial<RetryConfig
     return timeout(effectiveConfig.timeout, (done) => _retry(f, effectiveConfig, done));
 }
 
+export function retryDecorator<T, F extends (...args: any[]) => Promise<T>>(func: F, config?: Partial<RetryConfig<T>>): (...funcArgs: Parameters<F>) => Promise<T> {
+    return (...args: Parameters<F>) => retry(() => func(...args), config);
+}
+
 // tslint:disable-next-line
 export function customizeRetry<T>(customConfig: Partial<RetryConfig<T>>): (f: () => Promise<T>, config?: RetryConfig<T>) => Promise<T> {
     return (f, c) => {

test/retry-promise.decorator.test.ts

@@ -0,0 +1,33 @@
+import {expect} from "./index";
+import {customizeRetry, defaultRetryConfig, retry, retryDecorator, wait} from "../src/retry-promise";
+
+describe("Retry decorator test", () => {
+
+    it("can use decorator", async () => {
+        const asyncFunction: (s: string) => Promise<string> = async s => s;
+
+        const asyncFunctionDecorated = retryDecorator(asyncFunction);
+
+        expect(asyncFunctionDecorated("1")).to.eventually.eq("1")
+    });
+
+    it("can use decorator with custom config", async () => {
+        const asyncFunction: (s: string) => Promise<string> = async s => {
+            await wait(5);
+            return s;
+        };
+
+        const asyncFunctionDecorated = retryDecorator(asyncFunction, {timeout: 1});
+
+        expect(asyncFunctionDecorated("1")).to.be.rejectedWith("Timeout")
+    });
+
+    it("can use decorator with multiple args", async () => {
+        const asyncFunction: (s1: string, s2: string) => Promise<string> = async (s1, s2) => s1 + s2;
+
+        const asyncFunctionDecorated: (s1: string, s2: string) => Promise<string> = retryDecorator(asyncFunction);
+
+        expect(asyncFunctionDecorated("1", "2")).to.eventually.eq("12")
+    });
+
+});

test/retry-promise.demo.test.ts

@@ -1,5 +1,5 @@
 import {expect} from "./index";
-import {customizeRetry, defaultRetryConfig, retry, wait} from "../src/retry-promise";
+import {customizeRetry, defaultRetryConfig, retry, retryDecorator, wait} from "../src/retry-promise";
 
 describe("Retry Promise Demo", () => {
 
@@ -75,6 +75,17 @@ describe("Retry Promise Demo", () => {
         }
     });
 
+    it("can use decorator", async () => {
+
+        type AsyncFunc = (s: string) => Promise<string>
+
+        const asyncFunction: AsyncFunc = async s => s;
+
+        const asyncFunctionDecorated: AsyncFunc = retryDecorator(asyncFunction, {timeout: 1});
+
+        expect(asyncFunctionDecorated("1")).to.eventually.eq("1")
+    });
+
 });
 
 const browser = {