feat(reconnection strategy): add randomBackOffStrategy

* feat(reconnection strategy): add `randomBackOffStrategy`

* bump version + update changelog

CHANGELOG.md

@@ -1,3 +1,13 @@
+<a name="0.3.3"></a>
+## [0.3.3](https://github.com/sketch7/signalr-client/compare/0.3.2...0.3.3) (2017-12-05)
+
+
+### Features
+
+* **reconnection strategy:** add `randomBackOffStrategy` ([3bd046c](https://github.com/sketch7/signalr-client/commit/3bd046c))
+
+
+
 <a name="0.3.2"></a>
 ## [0.3.2](https://github.com/sketch7/signalr-client/compare/0.3.1...0.3.2) (2017-12-04)
 

README.md

@@ -24,9 +24,10 @@ SignalR client library built on top of `@aspnet/signalr-client`. This gives you
 * Update connection details easily without losing current connection state
 * Subscriptions are handled through `RxJS` streams
 * Reconnection strategies
-    * Random
-    * BackOff
-    * Custom
+    * Random strategy
+    * BackOff strategy
+    * Random BackOff strategy
+    * Custom strategy
 * Auto re-subscriptions after getting disconnected and re-connected (***in development***)
 * Contains minimal dependencies (`SignalR` and `RxJS` only)
 * `No constraints` with any framework
@@ -36,6 +37,7 @@ SignalR client library built on top of `@aspnet/signalr-client`. This gives you
 * Real world example (***coming soon***):
     * Client: Angular
     * Server: Microsoft Orleans integrated with SignalR
+* [Angular basic example](#angular-basic-example)
 
 ## Installation
 
@@ -65,7 +67,7 @@ You're all set! Now it's fully integrated with your Angular application.
 
 Continue from the [vanilla usage - step 2](#usage) onwards
 
-***Example***
+### Angular Basic Example
 ```ts
 import { HubConnectionFactory } from "@ssv/signalr-client";
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@ssv/signalr-client",
-  "version": "0.3.2",
+  "version": "0.3.3",
   "description": "SignalR client library built on top of @aspnet/signalr-client. This gives you more features and easier to use.",
   "keywords": [
     "sketch7",

src/hub-connection.model.ts

@@ -28,6 +28,7 @@ export interface ConnectionOptions extends IHubConnectionOptions {
 export interface ReconnectionStrategyOptions {
 	maximumAttempts?: number;
 	customStrategy?: (retryOptions: ReconnectionStrategyOptions, retryCount: number) => number;
+	randomBackOffStrategy?: RandomStrategyOptions;
 	randomStrategy?: RandomStrategyOptions;
 	backOffStrategy?: BackOffStrategyOptions;
 }

src/reconnection-strategy.ts

@@ -5,6 +5,9 @@ export function getReconnectionDelay(retryOptions: ReconnectionStrategyOptions,
 	if (retryOptions.customStrategy) {
 		return retryOptions.customStrategy(retryOptions, retryCount);
 	}
+	if (retryOptions.randomBackOffStrategy) {
+		return randomBackOffStrategyDelay(retryOptions.randomBackOffStrategy, retryCount);
+	}
 	if (retryOptions.backOffStrategy) {
 		return backOffStrategyDelay(retryOptions.backOffStrategy, retryCount);
 	}
@@ -18,10 +21,16 @@ function randomStrategyDelay(randomStrategy: RandomStrategyOptions) {
 	return random(randomStrategy.min, randomStrategy.max) * randomStrategy.intervalMs;
 }
 
+function randomBackOffStrategyDelay(randomStrategy: RandomStrategyOptions, retryCount: number) {
+	let maxValue = Math.min(retryCount, randomStrategy.max);
+	maxValue = randomStrategy.min >= maxValue ? (maxValue + 2) : maxValue;
+	return random(randomStrategy.min, maxValue) * randomStrategy.intervalMs;
+}
+
 function backOffStrategyDelay(backOffStrategy: BackOffStrategyOptions, retryCount: number) {
 	return Math.min(retryCount * backOffStrategy.delayRetriesMs, backOffStrategy.maxDelayRetriesMs);
 }
 
 function defaultStrategy(retryCount: number) {
-	return backOffStrategyDelay({ delayRetriesMs: 1000, maxDelayRetriesMs: 15000 }, retryCount);
+	return randomBackOffStrategyDelay({ min: 3, max: 15, intervalMs: 1000 }, retryCount);
 }