# Params

**Kind:** Type

**Source:** [`src/router.ts`](https://github.com/honojs/hono/blob/main/src/router.ts#L65)

Type representing a map of parameters.

`Params` represents a map of parameter names to their values in the router. It is used to pass route-specific data between route matching, navigation, and handler code.

## Definition

```ts
Record<string, string>
```

## Diagram

```mermaid
graph LR
  Route[Route pattern] --> Match[Route match]
  Match --> Params[Params]
  Params --> Handler[Route handler]
```

## Usage

```ts
import type { Params } from "./router";

const params: Params = {
  userId: "user-value",
  postSlug: "post-value",
};

function handleRoute(routeParams: Params) {
  const userId = routeParams.userId;
  const postSlug = routeParams.postSlug;

  return { userId, postSlug };
}

handleRoute(params);
```

## AI Coding Instructions

- Treat `Params` as route-derived data and keep parameter names aligned with the corresponding route pattern.
- Check for missing parameter values before relying on them in route handlers.
- Pass `Params` through router and handler boundaries instead of creating unrelated parameter object types.
- Keep parameter values in the format expected by the router before converting them for application logic.