docs: schema types

Signed-off-by: David Dal Busco <david.dalbusco@outlook.com>

Author: peterpeterparker

docs/reference/functions/typescript/schema.md

@@ -0,0 +1,43 @@
+# Schema Types
+
+Juno provides a type system built on top of [Zod](https://zod.dev/), extended with a few additional types you'll need when working with serverless functions.
+
+All types are available through `j`.
+
+```typescript
+import { j } from "@junobuild/schema";
+```
+
+---
+
+## Juno Types
+
+The following are specific types provided by Juno:
+
+### j.principal()
+
+Validates and represents an Internet Computer Principal.
+
+```typescript
+j.principal();
+```
+
+### j.uint8array()
+
+Validates and represents a `Uint8Array`.
+
+```typescript
+j.uint8array();
+```
+
+---
+
+## Zod Types
+
+All Zod types are available through `j`. Refer to the [Zod documentation](https://zod.dev/) for the full API reference.
+
+:::note
+
+`union` is not supported. Use `discriminatedUnion` instead.
+
+:::

sidebars.ts

@@ -407,6 +407,7 @@ const sidebars: SidebarsConfig = {
               "API reference for writing serverless functions with TypeScript."
           },
           items: [
+            "reference/functions/typescript/schema",
             "reference/functions/typescript/sdk",
             "reference/functions/typescript/utils",
             "reference/functions/typescript/ic-cdk",