Migrated Hosted Explorer to React (#360)

Co-authored-by: Victor Meng <vimeng@microsoft.com>
Co-authored-by: Steve Faulkner <stfaul@microsoft.com>

src/Platform/Hosted/extractFeatures.test.ts

@@ -0,0 +1,17 @@
+import { extractFeatures } from "./extractFeatures";
+
+describe("extractFeatures", () => {
+  it("correctly detects feature flags", () => {
+    // Search containing non-features, with Camelcase keys and uri encoded values
+    const params = new URLSearchParams(
+      "?platform=Hosted&feature.notebookserverurl=https%3A%2F%2Flocalhost%3A10001%2F12345%2Fnotebook&feature.notebookServerToken=token&feature.enablenotebooks=true&key=mykey"
+    );
+    const features = extractFeatures(params);
+
+    expect(features).toEqual({
+      notebookserverurl: "https://localhost:10001/12345/notebook",
+      notebookservertoken: "token",
+      enablenotebooks: "true"
+    });
+  });
+});