proposal: conditional content (#300)

Author: chdeskur

fern/products/docs/docs.yml

@@ -79,9 +79,9 @@ navigation:
         path: ./pages/component-library/custom-components/reusable-markdown.mdx
       - page: Custom React Components
         path: ./pages/component-library/custom-components/custom-react-components.mdx
-      - page: Global Variables
+      - page: Conditionally Rendered Content
         hidden: true
-        path: ./pages/component-library/custom-components/global-variables.mdx
+        path: ./pages/component-library/custom-components/conditional-rendering.mdx
   - section: Customization
     collapsed: true
     contents:

fern/products/docs/pages/component-library/custom-components/conditional-rendering.mdx

@@ -0,0 +1,49 @@
+---
+title: Conditionally Rendered Content
+---
+
+You can conditionally render content based on the instance or version of the docs, in addition to the role of an authenticated user.
+
+## Conditionally render content 
+
+### Between instances
+
+Define instances in your `docs.yml` file:
+
+```yaml docs.yml
+instances:
+  - url: fern-dev.docs.buildwithfern.com
+    name: development
+  - url: fern-prod.docs.buildwithfern.com
+    name: production
+```
+
+```mdx conditional-rendering.mdx
+<If instance={["development"]}>
+  This is a beta feature. It should only be available when the docs have been generated with the `development` instance.
+</If>
+
+<If instance={["production"]}>
+  This is a production feature. It should only be available when the docs have been generated with the `production` instance.
+</If>
+```
+
+### Between versions
+
+```mdx conditional-rendering.mdx
+<If version={["v1"]}>
+  This is an old feature. It should only be available when the user is on the `v1` version.
+</If>
+  
+<If version={["v2"]}>
+  This is a new feature. It should only be available when the user is on the `v2` version.
+</If>
+```
+
+### Based on the role of an authenticated user
+
+```mdx conditional-rendering.mdx
+<If viewer={["admin"]}>
+  This is an admin feature. It should only be available when the user is an admin.
+</If>
+```