detectFromQuery

Kind: Function

Source: src/middleware/language/language.ts

Part of: Middleware

Detects language from query parameter

detectFromQuery reads the language value from the incoming request query parameters. It is used by the language middleware to select the request language before downstream handlers process the request.

Signature

ts
function detectFromQuery(c: Context, options: DetectorOptions): string | undefined

Parameters

Returns: string | undefined

Diagram

mermaid
graph LR
  Request[Incoming request] --> Query[Query parameters]
  Query --> Detect[detectFromQuery]
  Detect --> Language[Detected language]
  Language --> Middleware[Language middleware]
  Middleware --> Handler[Request handler]

Usage

ts
import { detectFromQuery } from './language';

app.use((req, res, next) => {
  const language = detectFromQuery(req);

  if (language) {
    req.language = language;
  }

  next();
});

AI Coding Instructions

• Pass the incoming request object to detectFromQuery rather than reading query parameters in multiple middleware layers.
• Keep query parameter parsing inside this function so language detection has one code path.
• Handle an absent or invalid detected language in the calling middleware.
• Keep the detected language available on the request for downstream handlers when the middleware contract supports it.