Merge pull request #2996 from alysivji/spa-docs

[Docs] Add Single-Page Web Application pattern

docs/patterns/index.rst

@@ -42,3 +42,4 @@ Snippet Archives <http://flask.pocoo.org/snippets/>`_.
    requestchecksum
    celery
    subclassing
+   singlepageapplications

docs/patterns/singlepageapplications.rst

@@ -0,0 +1,24 @@
+Single-Page Applications
+========================
+
+Flask can be used to serve Single-Page Applications (SPA) by placing static
+files produced by your frontend framework in a subfolder inside of your
+project. You will also need to create a catch-all endpoint that routes all
+requests to your SPA.
+
+The following example demonstrates how to serve an SPA along with an API::
+
+    from flask import Flask, jsonify
+
+    app = Flask(__name__, static_folder='app')
+
+
+    @app.route("/heartbeat")
+    def heartbeat():
+        return jsonify({"status": "healthy"})
+
+
+    @app.route('/', defaults={'path': ''})
+    @app.route('/<path:path>')
+    def catch_all(path):
+        return app.send_static_file("index.html")