Add typescript declaration

Closes #22

example/app.ts

@@ -0,0 +1,34 @@
+import express, { Express } from "express";
+import Keyv from "keyv";
+import { Tgl, middleware, router, Toggle } from "tgl";
+
+const toggles: Toggle[] = [
+  {
+    name: "universal",
+    description: "Do we address the world, or the whole universe?",
+    defaultValue: false
+  },
+  {
+    name: "lasers",
+    description: "Enable lasers!!!",
+    defaultValue: true
+  }
+];
+const storage: Keyv<boolean> = new Keyv();
+const tgl: Tgl = new Tgl({ toggles, storage });
+
+tgl.get("hello");
+tgl.set("hello", true);
+
+const app: Express = express();
+
+app.use(middleware(tgl));
+
+app.get("/", (req, res) => {
+  const universal = req.tgl.get("universal");
+  res.send(universal ? "Hello, universe!" : "Hello, world!");
+});
+
+app.use("/tgl", router(tgl));
+
+module.exports = app;

lib/index.d.ts

@@ -0,0 +1,40 @@
+declare namespace Express {
+  interface Request extends TglRequest {}
+}
+
+declare interface TglRequest {
+  tgl?: Tgl;
+}
+
+declare module "tgl" {
+  import express from "express";
+  import Keyv from "keyv";
+
+  export interface Toggle {
+    name: string;
+    description: string;
+    defaultValue: boolean;
+  }
+
+  export function middleware(tgl: Tgl): express.Handler;
+
+  export function router(tgl: Tgl): express.Router;
+
+  export class Tgl {
+    constructor({
+      toggles,
+      storage,
+      interval
+    }: {
+      toggles: Toggle[];
+      storage: Keyv<boolean>;
+      interval?: number;
+    });
+
+    toggles: boolean[];
+
+    get(key: string): boolean;
+
+    set(key: string, value: boolean): Promise<void>;
+  }
+}

lib/index.js

@@ -25,7 +25,7 @@ class Tgl {
 
   async set(key, value) {
     this._cache[key] = value;
-    return this._storage.set(key, value);
+    await this._storage.set(key, value);
   }
 
   get(key) {

package.json

@@ -33,6 +33,8 @@
   "license": "MIT",
   "dependencies": {
     "@keyv/sqlite": "^2.0.1",
+    "@types/express": "^4.17.2",
+    "@types/keyv": "^3.1.0",
     "body-parser": "^1.19.0",
     "express": "^4.17.1",
     "keyv": "^4.0.0"