AJS Documentation about SPAs (#1051)

* WIP

* Documentation about SPAs

* Update src/connections/sources/catalog/libraries/website/javascript/spa.md

Co-authored-by: LRubin <[email protected]>

* Update src/connections/sources/catalog/libraries/website/javascript/spa.md

Co-authored-by: LRubin <[email protected]>

* Fixes

* Fixes

* Update src/connections/sources/catalog/libraries/website/javascript/spa.md

* quick edit

Co-authored-by: LRubin <[email protected]>
Co-authored-by: sanscontext <[email protected]>

Author: 3 people

src/connections/sources/catalog/libraries/website/javascript/spa.md

@@ -0,0 +1,46 @@
+---
+title: 'Single Page Apps with Analytics.js'
+hidden: true
+strat: ajs
+---
+
+Analytics.js can work with your single-page applications built with technologies such as React or Vue.
+
+## Integrating with your build tooling
+
+If you have a single-page application and plan to use Segment a lot, you might need to add [a Segment server analytics library](/docs/connections/sources/catalog/#server) to your build system.  You can do this using Segment's `analytics-node` package instead of using the Analytics.js javascript code snippet. The Analytics-Node package works like any standard node-js dependency.
+
+First add the package as a dependency:
+
+```sh
+$ npm install analytics-node
+```
+
+or, if you are using `yarn`:
+
+```sh
+$ yarn add analytics-node
+```
+
+Once installed, you can import `analytics-node` and instrument your events the same way you would with Analytics.js.  The example implementation below is in React:
+
+```js
+import Analytics from 'analytics-node'
+
+const analytics = new Analytics("YOUR WRITE KEY")
+
+class ShoppingCartButton {
+    onPurchase = () => {
+        analytics.Track("Item Purchased", {
+            itemId: "abc"
+        })
+    }
+
+    render() {
+        return <button onClick={this.onPurchase}>Buy Item</button>
+    }
+
+}
+```
+
+**Note:** Segment's `analytics-node` package does not support [device-mode destinations](/docs/utils/cmodes-compare/) or some browser specific features that Analytics.js supports.