gg-express/readme.md

**GG-Express** is an Express.js wrapper that enforces strong type requirements for `GET`, `POST`, `PUT`, and `DELETE` methods. It ensures that `req.query` and `req.body` follow strict structure definitions and automatically generates an `apiConnector` cla

# 🚀 GG-Express

**GG-Express** is an Express.js wrapper that enforces strong type requirements for `GET`, `POST`, `PUT`, and `DELETE` methods. It ensures that `req.query` and `req.body` follow strict structure definitions and automatically generates an `apiConnector` class file for easy use in front-end development. 🎉🎉🎉

## ✨ Features

- **Strict Type Enforcement**: Ensures that `req.query` and `req.body` follow the declared types.
- **Auto-Generated API Connector**: Automatically creates a static API class for strongly-typed parameters.
- **Seamless Front-End Integration**: Simplifies the connection between the back-end and front-end by enforcing consistency.

## 🔑 Key Points

- **Strict Parameter Enforcement**: GG-Express ensures only the declared parameters are accessible in `req.body` or `req.query`.
- **Type-Safe Responses**: Ensures that the backend responds with a structure that matches front-end expectations.
- **API Connector Generation**: It automatically generates a type-safe API connector class file for the front-end.

## 🛠 Installation

```bash
npm install gg-express
```

🧑‍💻 Use Case in Backend

```typescript
import express from "express"
import GGExpress from "gg-express"
const app = express()

// Initialize GG-Express with backend and frontend file paths
const ggapp = new GGExpress(app, [
  "./server/output-path-for-apiConnector.ts", // Path to generate apiConnector.ts backend file
  "./myapp/output-path-for-apiConnector.ts", // Path to generate apiConnector.ts frontend file
])

// Example of a POST request with enforced parameters
ggapp.post(
  "/api/item",
  {
    requireParams: {
      parameter: { lotNumber: "number" },
      dataType: "arrayObject",
      structure: {
        id: "number",
        name: "string",
        price: "number",
      },
    },
    responseStructure: {
      parameter: { numberOfPeople: "number", itemName: "string" },
      dataType: "arrayObject",
      structure: {
        id: "number",
        name: "string",
      },
    },
  },
  (req, res, next) => {
    // Access only the required parameters declared above
    const data = req.body.data

    // Response structure follows the predefined format
    return res.json({
      message: "",
      status: "SUCCESS",
      data: [],
      parameter: {
        itemName: "",
        numberOfPeople: 2,
      },
    })
  }
)

// Start the server and generate the API files
app.listen(3000, () => {
  ggapp.generateAPIFiles() // Generates the apiConnector class for front-end use
})
```

📲 Use Case in Frontend
• The apiConnector.ts file will be automatically generated by the GGExpress class you configured in the backend

```typescript
import GGApi from "apiConnector.ts"

const api = new GGApi()
const response = await api.post("/api/item", {
  parameter: {
    lotNumber: 2,
  },
  data: [
    {
      id: 1032,
      name: "machete",
      price: 4599,
    },
  ],
})
console.log(response.data)
// Expected data structure:
//  parameter: { numberOfPeople: number, itemName: string },
//       structure: {
//         id: number,
//         name: string,
//       }[],
// }
```

## 🔑 Keywords

- Express.js
- TypeScript
- API wrapper
- Type-safe API
- Backend-frontend integration