From 449a5e2d87e20f1dc33944eee4debb473a15045d Mon Sep 17 00:00:00 2001
From: Jonas L <jonas@determapp.de>
Date: Wed, 9 May 2018 15:20:01 +0200
Subject: [PATCH] Add rolling rate limiter

---
 types/rolling-rate-limiter/index.d.ts         | 38 +++++++++++++++++++
 .../rolling-rate-limiter-tests.ts             | 36 ++++++++++++++++++
 types/rolling-rate-limiter/tsconfig.json      | 23 +++++++++++
 types/rolling-rate-limiter/tslint.json        |  1 +
 4 files changed, 98 insertions(+)
 create mode 100644 types/rolling-rate-limiter/index.d.ts
 create mode 100644 types/rolling-rate-limiter/rolling-rate-limiter-tests.ts
 create mode 100644 types/rolling-rate-limiter/tsconfig.json
 create mode 100644 types/rolling-rate-limiter/tslint.json

diff --git a/types/rolling-rate-limiter/index.d.ts b/types/rolling-rate-limiter/index.d.ts
new file mode 100644
index 0000000000..0de8235fc2
--- /dev/null
+++ b/types/rolling-rate-limiter/index.d.ts
@@ -0,0 +1,38 @@
+// Type definitions for rolling-rate-limiter 0.1
+// Project: https://github.com/peterkhayes/rolling-rate-limiter
+// Definitions by: Jonas Lochmann <https://github.com/l-jonas>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+
+export = RollingRateLimiter;
+
+declare function RollingRateLimiter(options: RollingRateLimiter.InMemoryOptions): RollingRateLimiter.SyncOrAsyncLimiter;
+declare function RollingRateLimiter(options: RollingRateLimiter.WithRedisOptions): RollingRateLimiter.AsyncLimiter;
+
+declare namespace RollingRateLimiter {
+  interface GeneralOptions {
+    interval: number;
+    maxInInterval: number;
+    minDifference?: number;
+  }
+
+  interface RedisOptions {
+    redis: CompatibleRedisClient;
+    namespace?: string;
+  }
+
+  interface CompatibleRedisClient {
+    multi: () => any;
+  }
+
+  type InMemoryOptions = GeneralOptions;
+  type WithRedisOptions = GeneralOptions & RedisOptions;
+
+  type AsyncLimiterWithToken = (token: string, callback: AsyncLimiterCallback) => void;
+  type AsyncLimiterWithoutToken = (callback: AsyncLimiterCallback) => void;
+  type AsyncLimiterCallback = (err: any, timeLeft: number, actionsLeft: number) => void;
+  type AsyncLimiter = AsyncLimiterWithToken & AsyncLimiterWithToken;
+
+  type SyncLimiter = (token?: string) => number;
+
+  type SyncOrAsyncLimiter = SyncLimiter & AsyncLimiter;
+}
diff --git a/types/rolling-rate-limiter/rolling-rate-limiter-tests.ts b/types/rolling-rate-limiter/rolling-rate-limiter-tests.ts
new file mode 100644
index 0000000000..1318b8d425
--- /dev/null
+++ b/types/rolling-rate-limiter/rolling-rate-limiter-tests.ts
@@ -0,0 +1,36 @@
+import * as RateLimiter from 'rolling-rate-limiter';
+
+/*
+  Setup:
+*/
+
+const limiter = RateLimiter({
+  // in miliseconds
+  interval: 1000,
+  maxInInterval: 10,
+  // optional: the minimum time (in miliseconds) between any two actions
+  minDifference: 100
+});
+
+/*
+  Action:
+*/
+
+function attemptAction(userId: string) {
+  // Argument should be a unique identifier for a user if one exists.
+  // If none is provided, the limiter will not differentiate between users.
+  const timeLeft = limiter(userId);
+
+  if (timeLeft > 0) {
+    // limit was exceeded, action should not be allowed
+    // timeLeft is the number of ms until the next action will be allowed
+    // note that this can be treated as a boolean, since 0 is falsy
+  } else {
+    // limit was not exceeded, action should be allowed
+  }
+}
+
+/*
+  Note that the in-memory version can also operate asynchronously.
+  The syntax is identical to the redis implementation below.
+*/
diff --git a/types/rolling-rate-limiter/tsconfig.json b/types/rolling-rate-limiter/tsconfig.json
new file mode 100644
index 0000000000..0b526f946e
--- /dev/null
+++ b/types/rolling-rate-limiter/tsconfig.json
@@ -0,0 +1,23 @@
+{
+    "compilerOptions": {
+        "module": "commonjs",
+        "lib": [
+            "es6"
+        ],
+        "noImplicitAny": true,
+        "noImplicitThis": true,
+        "strictNullChecks": true,
+        "strictFunctionTypes": true,
+        "baseUrl": "../",
+        "typeRoots": [
+            "../"
+        ],
+        "types": [],
+        "noEmit": true,
+        "forceConsistentCasingInFileNames": true
+    },
+    "files": [
+        "index.d.ts",
+        "rolling-rate-limiter-tests.ts"
+    ]
+}
diff --git a/types/rolling-rate-limiter/tslint.json b/types/rolling-rate-limiter/tslint.json
new file mode 100644
index 0000000000..3db14f85ea
--- /dev/null
+++ b/types/rolling-rate-limiter/tslint.json
@@ -0,0 +1 @@
+{ "extends": "dtslint/dt.json" }