docs: example assertion typescript (#472)

* docs: example assertion typescript

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

* 📄 Update LLMs.txt snapshot for PR review

---------

Signed-off-by: David Dal Busco <david.dalbusco@outlook.com>
Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

Author: peterpeterparker

.llms-snapshots/llms-full.txt

@@ -2231,6 +2231,10 @@ Write serverless backend logic for your app using TypeScript or Rust. These exam
 
 4 items](/docs/examples/functions/rust.md)
 
+[## 🗃️ TypeScript
+
+1 item](/docs/examples/functions/typescript.md)
+
 # Angular Example
 
 This project is a note-taking app template built with **Angular**, **TypeScript**, and **Tailwind CSS**, designed to demonstrate integration with Juno for app development. It showcases authentication, data storage, and file storage using Juno's Satellite container.
@@ -3173,6 +3177,14 @@ An example showing how to dynamically generate and store assets (like JSON) in S
 
 An example showing how to call external canisters (e.g., ICRC ledger) from a serverless function written in Rust using Juno Satellites.](/docs/examples/functions/rust/canister-calls.md)
 
+# TypeScript
+
+Examples of writing serverless functions in TypeScript for Juno. Includes patterns like custom assertions, data manipulation and calls.
+
+[## 📄️ Assertion
+
+An example demonstrating how to write custom assertions in TypeScript for Juno serverless functions.](/docs/examples/functions/typescript/assertion.md)
+
 # Rust Assertion Example
 
 This example demonstrates how to write a **custom assertion** in **Rust** for a Juno **serverless function**. It shows how to intercept and validate data operations—such as rejecting specific content—before it's written to the datastore.
@@ -3329,7 +3341,7 @@ It’s a great reference for more advanced setups and multi-collection coordinat
 ## References
 
 *   [Serverless Functions Guide](/docs/guides/rust.md)
-*   [Rust Functions Development](/docs/build/functions.md)
+*   [Functions Development](/docs/build/functions.md)
 *   [Rust SDK Reference](/docs/reference/functions/rust/sdk.md)
 *   [Rust Utils Reference](/docs/reference/functions/rust/utils.md)
 *   [Run Local Development](/docs/guides/local-development.md)
@@ -3513,7 +3525,7 @@ It’s a great reference for more advanced setups and multi-collection coordinat
 ## References
 
 *   [Serverless Functions Guide](/docs/guides/rust.md)
-*   [Rust Functions Development](/docs/build/functions.md)
+*   [Functions Development](/docs/build/functions.md)
 *   [Rust SDK Reference](/docs/reference/functions/rust/sdk.md)
 *   [Rust Utils Reference](/docs/reference/functions/rust/utils.md)
 *   [Run Local Development](/docs/guides/local-development.md)
@@ -3676,7 +3688,7 @@ juno functions buildjuno functions upgrade
 ## References
 
 *   [Serverless Functions Guide](/docs/guides/rust.md)
-*   [Rust Functions Development](/docs/build/functions.md)
+*   [Functions Development](/docs/build/functions.md)
 *   [Rust SDK Reference](/docs/reference/functions/rust/sdk.md)
 *   [Rust Utils Reference](/docs/reference/functions/rust/utils.md)
 *   [Run Local Development](/docs/guides/local-development.md)
@@ -3850,7 +3862,7 @@ It’s a great reference for more advanced setups and multi-collection coordinat
 ## References
 
 *   [Serverless Functions Guide](/docs/guides/rust.md)
-*   [Rust Functions Development](/docs/build/functions.md)
+*   [Functions Development](/docs/build/functions.md)
 *   [Rust SDK Reference](/docs/reference/functions/rust/sdk.md)
 *   [Rust Utils Reference](/docs/reference/functions/rust/utils.md)
 *   [Run Local Development](/docs/guides/local-development.md)
@@ -3870,6 +3882,171 @@ These crates are used to build and extend serverless functions in Rust with Juno
 *   [junobuild-shared](https://docs.rs/junobuild-shared): Shared types and helpers for Juno projects. Used by all containers including the Console.
 *   [junobuild-storage](https://docs.rs/junobuild-storage): Storage helpers for working with assets and HTTP headers in Juno.
 
+# TypeScript Assertion Example
+
+This example demonstrates how to write a **custom assertion** in **TypeScript** for a Juno **serverless function**. It shows how to intercept and validate data operations—such as rejecting specific content—before it's written to the datastore.
+
+The project includes a minimal frontend to help trigger and test the logic, but the primary focus is the backend assertion.
+
+You can browse the source code here: [github.com/junobuild/examples/tree/main/functions/typescript/assertions](https://github.com/junobuild/examples/tree/main/functions/typescript/assertions)
+
+---
+
+## Folder Structure
+
+```
+typescript/assertions/├── src/│   ├── satellite/           # TypeScript Satellite serverless function│   │   └── index.ts         # Main TypeScript logic for Satellite│   ├── types/│   │   └── note.ts          # Note type and schema│   └── components/          # Minimal frontend React components├── juno.config.ts           # Juno Satellite configuration├── package.json             # Frontend and serverless dependencies└── ...
+```
+
+---
+
+## Key Features
+
+*   **Custom Assertions in TypeScript**: Demonstrates how to reject or validate data before it's saved, using TypeScript serverless functions.
+*   **Serverless Integration**: Runs as a Satellite function and integrates with Juno's datastore and authentication system.
+*   **Minimal UI for Testing**: A simple frontend is included to test and demonstrate the assertion logic in action.
+
+---
+
+## Main Backend Components
+
+*   **src/satellite/index.ts**: The core TypeScript logic for the Satellite serverless function. Implements the custom assertions (e.g., only allow certain valid inputs, etc.).
+*   **src/satellite/Cargo.toml**: TypeScript package configuration for the Satellite function.
+
+---
+
+## Example: Custom Assertion in TypeScript
+
+Here’s the actual TypeScript logic from `index.ts`:
+
+```
+import { type AssertSetDoc, defineAssert } from "@junobuild/functions";import { decodeDocData } from "@junobuild/functions/sdk";import { type NoteData, NoteDataSchema } from "../types/note";export const assertSetDoc = defineAssert<AssertSetDoc>({  collections: ["notes"],  assert: (context) => {    const note = decodeDocData<NoteData>(context.data.data.proposed.data);    NoteDataSchema.parse(note);    if (note.text.toLowerCase().includes("hello")) {      console.log("❌ Rejected note containing 'hello':", note.text);      throw new Error("The note should not contain the keyword 'hello'.");    }  }});
+```
+
+**Explanation:**
+
+*   Defines a `NoteData` type and `NoteDataSchema` using [zod](https://zod.dev/) for runtime validation.
+*   Uses `defineAssert` to create a custom assertion for the `notes` collection.
+*   When a note is created or updated, the assertion checks if the note's text contains the word "hello" (case-insensitive).
+*   If it does, the note is rejected and an error is thrown; otherwise, the note is accepted.
+*   Prints a message to the log for both accepted and rejected notes.
+
+---
+
+## How to Run
+
+1.  **Clone the repo**:
+
+```
+git clone https://github.com/junobuild/examplescd typescript/assertions
+```
+
+2. **Install dependencies**:
+
+```
+npm install
+```
+
+3. **Start Juno local emulator**:
+
+**Important:**
+
+Requires the Juno CLI to be available `npm i -g @junobuild/cli`
+
+```
+juno dev start
+```
+
+4. **Create a Satellite** for local dev:
+
+*   Visit [http://localhost:5866](http://localhost:5866) and follow the instructions.
+*   Update `juno.config.ts` with your Satellite ID.
+
+5.  **Create required collections**:
+
+*   `notes` in Datastore: [http://localhost:5866/datastore](http://localhost:5866/datastore)
+*   `images` in Storage: [http://localhost:5866/storage](http://localhost:5866/storage)
+
+6.  **Start the frontend dev server** (in a separate terminal):
+
+```
+npm run dev
+```
+
+7.  **Build the serverless functions** (in a separate terminal):
+
+```
+juno functions build
+```
+
+The emulator will automatically upgrade your Satellite and live reload the changes.
+
+---
+
+## Juno-Specific Configuration
+
+*   **juno.config.ts**: Defines Satellite IDs for development/production, build source, and predeploy steps. See the [Configuration reference](/docs/reference/configuration.md) for details.
+*   **vite.config.ts**: Registers the `juno` plugin to inject environment variables automatically. See the [Vite Plugin reference](/docs/reference/plugins.md#vite-plugin) for more information.
+
+---
+
+## Production Deployment
+
+*   Create a Satellite on the [Juno Console](https://console.juno.build) for mainnet.
+*   Update `juno.config.ts` with the production Satellite ID.
+*   Build and deploy the frontend:
+
+```
+npm run buildjuno deploy
+```
+
+*   Build and upgrade the serverless functions:
+
+```
+juno functions buildjuno functions upgrade
+```
+
+---
+
+## Notes
+
+*   This example focuses on the TypeScript serverless function; the frontend is intentionally minimal and only included for demonstration purposes.
+*   Use this project as a starting point for writing custom assertions and backend logic in TypeScript with Juno.
+
+---
+
+## Real-World Example
+
+Want to see how assertions and serverless logic are used in a live project?
+
+Check out [cycles.watch](https://cycles.watch), an open-source app built with Juno:
+
+*   GitHub: [github.com/peterpeterparker/cycles.watch](https://github.com/peterpeterparker/cycles.watch)
+*   Example logic: [src/satellite/index.ts](https://github.com/peterpeterparker/cycles.watch/blob/main/src/satellite/index.ts)
+
+This app uses:
+
+*   `assertSetDoc` to validate requests
+*   `onSetDoc` to implement a swap-like feature that performs various canister calls
+*   Service modules to keep logic organized
+*   A real-world pattern for chaining calls and document insertions with assertions
+
+It’s a great reference for more advanced setups and orchestration.
+
+---
+
+## References
+
+*   [Serverless Functions Guide](/docs/guides/typescript.md)
+*   [Functions Development](/docs/build/functions.md)
+*   [TypeScript SDK Reference](/docs/reference/functions/typescript/sdk.md)
+*   [TypeScript ic-cdk Reference](/docs/reference/functions/typescript/ic-cdk.md)
+*   [TypeScript Utils Reference](/docs/reference/functions/typescript/utils.md)
+*   [Run Local Development](/docs/guides/local-development.md)
+*   [CLI Reference](/docs/reference/cli.md)
+*   [Configuration Reference](/docs/reference/configuration.md)
+*   [Datastore Collections](/docs/build/datastore/collections.md)
+
 # Using Juno with AI
 
 If you're using AI to build with Juno, you can use our `llms.txt` files to help AI tools better understand the platform.

.llms-snapshots/llms.txt

@@ -64,6 +64,7 @@ Juno is your self-contained serverless platform for building full-stack web apps
 ## Examples - Functions
 
 - [Rust](https://juno.build/docs/examples/functions/rust.md): Examples of writing serverless functions in Rust for Juno. Includes patterns like custom assertions, data manipulation and calls.
+- [TypeScript](https://juno.build/docs/examples/functions/typescript.md): Examples of writing serverless functions in TypeScript for Juno. Includes patterns like custom assertions, data manipulation and calls.
 
 ## Examples - Functions - Rust
 
@@ -72,6 +73,10 @@ Juno is your self-contained serverless platform for building full-stack web apps
 - [Generating Assets with Rust Serverless Functions](https://juno.build/docs/examples/functions/rust/generating-assets.md): An example showing how to dynamically generate and store assets (like JSON) in Storage using Rust in Juno Satellites.
 - [Mutating Documents with Rust Hooks](https://juno.build/docs/examples/functions/rust/mutating-docs.md): An example demonstrating how to modify and re-save documents in Juno Satellites using Rust hooks.
 
+## Examples - Functions - Typescript
+  
+- [TypeScript Assertions Example](https://juno.build/docs/examples/functions/typescript/assertion.md): An example demonstrating how to write custom assertions in TypeScript for Juno serverless functions.
+
 ## Guides
 
 - [AI](https://juno.build/docs/guides/ai.md): Learn how to use Juno's llms.txt files to provide AI tools with better context for building serverless functions, deploying satellites, and integrating the SDK.

docs/examples/functions/rust/components/references.md

@@ -1,7 +1,7 @@
 ## References
 
 - [Serverless Functions Guide](../../../../guides/rust.mdx)
-- [Rust Functions Development](../../../../build/functions/index.md)
+- [Functions Development](../../../../build/functions/index.md)
 - [Rust SDK Reference](../../../../reference/functions/rust/sdk.mdx)
 - [Rust Utils Reference](../../../../reference/functions/rust/utils.mdx)
 - [Run Local Development](../../../../guides/local-development.mdx)