Added typescript webhook example

examples/webhook-signing/.gitignore

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+.env
+express-ts.js

examples/webhook-signing/express-ts.ts

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+import Stripe from 'stripe';
+import express from 'express';
+import bodyParser from 'body-parser';
+import dotenv from 'dotenv';
+
+dotenv.config();
+
+const stripe: Stripe = new Stripe(process.env.STRIPE_API_KEY!, {
+  apiVersion: '2019-12-03',
+  typescript: true,
+});
+
+/**
+ * You'll need to make sure this is externally accessible. ngrok (https://ngrok.com/)
+ * makes this really easy.
+ *
+ * Alternatively, you could use the stripe-cli in forward mode: https://github.com/stripe/stripe-cli
+ *
+ * To run this file, just provide your Secret API Key and Webhook Secret in a .env file in this directory like so:
+ *
+ * STRIPE_API_KEY=sk_test_XXX
+ * WEBHOOK_SECRET=whsec_XXX
+ *
+ * Then run "npm run tsc", which will convert this TypeScript file to JS and then run it.
+ *
+ * For use with the stripe-cli, run the following:
+ *
+ * 1. "stripe listen --forward-to localhost:3000/webhooks"
+ * 2. Copy the provided webhook signing secret to your .env file
+ * 3. In a new terminal window: "npm run tsc"
+ * 4. In yet another new terminal window: "stripe trigger payment_intents.succeeded"
+ */
+
+const webhookSecret: string = process.env.WEBHOOK_SECRET!;
+const app: express.Application = express();
+
+// Only use the raw body parser for webhooks
+app.use(
+  (
+    req: express.Request,
+    res: express.Response,
+    next: express.NextFunction
+  ): void => {
+    if (req.originalUrl === '/webhooks') {
+      next();
+    } else {
+      bodyParser.json()(req, res, next);
+    }
+  }
+);
+
+// Stripe requires the raw body to construct the event
+app.post(
+  '/webhooks',
+  bodyParser.raw({type: 'application/json'}),
+  (req: express.Request, res: express.Response): express.Response | void => {
+    const sig: string = req.headers['stripe-signature'] as string;
+
+    let event: Stripe.Event;
+
+    try {
+      event = stripe.webhooks.constructEvent(req.body, sig, webhookSecret);
+    } catch (err) {
+      // On error, return the error message
+      return res.status(400).send(`Webhook Error: ${err.message}`);
+    }
+
+    // Do something with event
+    console.log('Success:', event.id);
+
+    // Cast event data to Stripe object
+    switch (event.type) {
+      case 'payment_intent.succeeded':
+        const pi = event.data.object as Stripe.PaymentIntent;
+        console.log(`PaymentIntent status: ${pi.status}`);
+        break;
+    }
+
+    // Return a response to acknowledge receipt of the event
+    return res.json({received: true});
+  }
+);
+
+app.listen(
+  3000,
+  (): void => {
+    console.log('Example app listening on port 3000!');
+  }
+);