docs: finish the remaining 5.x/4.x API reference consistency items

docs/content.md

@@ -134,6 +134,20 @@ src/content/api/
 - Versioned: `/en/5x/api/application` → Express 5.x application API
 - Non-versioned: `/en/api/application` → Defaults to Express 5.x
 
+### Style Conventions
+
+The reference pages for every version follow the same conventions, so that switching between
+Express 4.x and 5.x only shows real API differences:
+
+- Property and method sections are listed alphabetically, so `req.host` comes before `req.hostname`.
+- Result comments in code samples use single quotes, matching the Prettier `singleQuote` setting:
+  `res.type('png'); // => 'image/png'`. Double quotes are kept only where the sample shows JSON or a
+  raw HTTP header.
+- The frontmatter `description` of the request and response pages repeats the opening sentence of the
+  page, which refers to the objects as `req` and `res` rather than spelling out their full names.
+
+`tests/unit/api-docs-style.test.mjs` checks these conventions, and it runs as part of `npm run test:unit`.
+
 ## Versioning
 
 The Express.js documentation supports multiple versions. Content is organized by version in both the `docs` and `api` collections.

src/content/api/4x/api/application/index.mdx

@@ -560,7 +560,7 @@ app.get('title');
 
 app.set('title', 'My Site');
 app.get('title');
-// => "My Site"
+// => 'My Site'
 ```
 
 ### app.get()

src/content/api/4x/api/request/index.mdx

@@ -244,6 +244,22 @@ console.dir(req.fresh);
 // => true
 ```
 
+### req.host
+
+<Signature type="String" deprecated="v4.5.0" />
+
+<Alert type="alert">
+
+`req.host` is a deprecated alias of [`req.hostname`](#reqhostname) and returns the same value — the hostname with the port number stripped off. It has emitted a deprecation warning since Express v4.5.0. Use `req.hostname` instead.
+
+</Alert>
+
+```js
+// Host: "example.com:3000"
+console.dir(req.host);
+// => 'example.com'
+```
+
 ### req.hostname
 
 <Signature type="String" />
@@ -272,22 +288,6 @@ console.dir(req.hostname);
 // => 'example.com'
 ```
 
-### req.host
-
-<Signature type="String" deprecated="v4.5.0" />
-
-<Alert type="alert">
-
-`req.host` is a deprecated alias of [`req.hostname`](#reqhostname) and returns the same value — the hostname with the port number stripped off. It has emitted a deprecation warning since Express v4.5.0. Use `req.hostname` instead.
-
-</Alert>
-
-```js
-// Host: "example.com:3000"
-console.dir(req.host);
-// => 'example.com'
-```
-
 ### req.ip
 
 <Signature type="String" />
@@ -671,17 +671,17 @@ list or array, the method returns the _best_ match (if any).
 ```js
 // Accept: text/html
 req.accepts('html');
-// => "html"
+// => 'html'
 
 // Accept: text/*, application/json
 req.accepts('html');
-// => "html"
+// => 'html'
 req.accepts('text/html');
-// => "text/html"
+// => 'text/html'
 req.accepts(['json', 'text']);
-// => "json"
+// => 'json'
 req.accepts('application/json');
-// => "application/json"
+// => 'application/json'
 
 // Accept: text/*, application/json
 req.accepts('image/png');
@@ -690,7 +690,7 @@ req.accepts('png');
 
 // Accept: text/*;q=.5, application/json
 req.accepts(['html', 'json']);
-// => "json"
+// => 'json'
 ```
 
 For more information, or if you have issues or concerns, see [accepts](https://github.com/expressjs/accepts).
@@ -856,10 +856,10 @@ The `Referrer` and `Referer` fields are interchangeable.
 
 ```js
 req.get('Content-Type');
-// => "text/plain"
+// => 'text/plain'
 
 req.get('content-type');
-// => "text/plain"
+// => 'text/plain'
 
 req.get('Something');
 // => undefined
@@ -943,15 +943,15 @@ Returns the value of param `name` when present.
 ```js
 // ?name=tobi
 req.param('name');
-// => "tobi"
+// => 'tobi'
 
 // POST name=tobi
 req.param('name');
-// => "tobi"
+// => 'tobi'
 
 // /user/tobi for /user/:name
 req.param('name');
-// => "tobi"
+// => 'tobi'
 ```
 
 Lookup is performed in the following order:

src/content/api/4x/api/response/index.mdx

@@ -572,7 +572,7 @@ The match is case-insensitive.
 
 ```js
 res.get('Content-Type');
-// => "text/plain"
+// => 'text/plain'
 ```
 
 ### res.json()

src/content/api/5x/api/application/index.mdx

@@ -585,7 +585,7 @@ app.get('title');
 
 app.set('title', 'My Site');
 app.get('title');
-// => "My Site"
+// => 'My Site'
 ```
 
 ### app.get()

src/content/api/5x/api/request/index.mdx

@@ -1,6 +1,6 @@
 ---
 title: Request Object
-description: The request object represents the HTTP request and has properties for the request query string, parameters, body, HTTP headers, and so on
+description: The req object represents the HTTP request and has properties for the request query string, parameters, body, HTTP headers, and so on
 ---
 
 import Alert from '@components/primitives/Alert/Alert.astro';
@@ -211,7 +211,7 @@ contains cookies sent by the request. If the request contains no cookies, it def
 ```js
 // Cookie: name=tj
 console.dir(req.cookies.name);
-// => "tj"
+// => 'tj'
 ```
 
 If the cookie has been signed, you have to use [req.signedCookies](#reqsignedcookies).
@@ -292,7 +292,7 @@ the value of this property is derived from the left-most entry in the
 
 ```js
 console.dir(req.ip);
-// => "127.0.0.1"
+// => '127.0.0.1'
 ```
 
 ### req.ips
@@ -361,7 +361,7 @@ the "mounting" feature of [app.use()](/api/application/#appuse) will rewrite `re
 ```js
 // GET /search?q=something
 console.dir(req.originalUrl);
-// => "/search?q=something"
+// => '/search?q=something'
 ```
 
 `req.originalUrl` is available both in middleware and router objects, and is a
@@ -398,7 +398,7 @@ This property is an object containing properties mapped to the [named route "par
 ```js
 // GET /user/tj
 console.dir(req.params.name);
-// => "tj"
+// => 'tj'
 ```
 
 Properties corresponding to wildcard parameters are arrays containing separate path segments split on `/`:
@@ -433,7 +433,7 @@ When you use a regular expression for the route definition, capture groups are p
 app.use(/^\/file\/(.*)$/, (req, res) => {
   // GET /file/javascripts/jquery.js
   console.dir(req.params[0]);
-  // => "javascripts/jquery.js"
+  // => 'javascripts/jquery.js'
 });
 ```
 
@@ -443,7 +443,7 @@ import { type Request, type Response } from 'express';
 app.use(/^\/file\/(.*)$/, (req: Request, res: Response) => {
   // GET /file/javascripts/jquery.js
   console.dir(req.params[0]);
-  // => "javascripts/jquery.js"
+  // => 'javascripts/jquery.js'
 });
 ```
 
@@ -468,7 +468,7 @@ Contains the path part of the request URL.
 ```js
 // example.com/users?sort=desc
 console.dir(req.path);
-// => "/users"
+// => '/users'
 ```
 
 <Alert type="info">
@@ -490,7 +490,7 @@ This header can be set by the client or by the proxy.
 
 ```js
 console.dir(req.protocol);
-// => "http"
+// => 'http'
 ```
 
 ### req.query
@@ -637,7 +637,7 @@ If no signed cookies are sent, the property defaults to `{}`.
 ```js
 // Cookie: user=tobi.CP7AWaXDfAKIRfH49dQzKJx7sKzzSoPq7/AcBBRVwlI3
 console.dir(req.signedCookies.user);
-// => "tobi"
+// => 'tobi'
 ```
 
 For more information, issues, or concerns, see [cookie-parser](https://github.com/expressjs/cookie-parser).
@@ -663,7 +663,7 @@ An array of subdomains in the domain name of the request.
 ```js
 // Host: "tobi.ferrets.example.com"
 console.dir(req.subdomains);
-// => ["ferrets", "tobi"]
+// => ['ferrets', 'tobi']
 ```
 
 The application property `subdomain offset`, which defaults to 2, is used for determining the
@@ -708,17 +708,17 @@ list or array, the method returns the _best_ match (if any).
 ```js
 // Accept: text/html
 req.accepts('html');
-// => "html"
+// => 'html'
 
 // Accept: text/*, application/json
 req.accepts('html');
-// => "html"
+// => 'html'
 req.accepts('text/html');
-// => "text/html"
+// => 'text/html'
 req.accepts(['json', 'text']);
-// => "json"
+// => 'json'
 req.accepts('application/json');
-// => "application/json"
+// => 'application/json'
 
 // Accept: text/*, application/json
 req.accepts('image/png');
@@ -727,7 +727,7 @@ req.accepts('png');
 
 // Accept: text/*;q=.5, application/json
 req.accepts(['html', 'json']);
-// => "json"
+// => 'json'
 ```
 
 For more information, or if you have issues or concerns, see [accepts](https://github.com/expressjs/accepts).
@@ -832,10 +832,10 @@ The `Referrer` and `Referer` fields are interchangeable.
 
 ```js
 req.get('Content-Type');
-// => "text/plain"
+// => 'text/plain'
 
 req.get('content-type');
-// => "text/plain"
+// => 'text/plain'
 
 req.get('Something');
 // => undefined

src/content/api/5x/api/response/index.mdx

@@ -1,6 +1,6 @@
 ---
 title: Response
-description: The response object represents the HTTP response that an Express app sends when it gets an HTTP request.
+description: The res object represents the HTTP response that an Express app sends when it gets an HTTP request.
 ---
 
 import Alert from '@components/primitives/Alert/Alert.astro';
@@ -564,7 +564,7 @@ The match is case-insensitive.
 
 ```js
 res.get('Content-Type');
-// => "text/plain"
+// => 'text/plain'
 ```
 
 ### res.json()
@@ -1104,7 +1104,7 @@ res.type('.html'); // => 'text/html'
 res.type('html'); // => 'text/html'
 res.type('json'); // => 'application/json'
 res.type('application/json'); // => 'application/json'
-res.type('png'); // => image/png:
+res.type('png'); // => 'image/png'
 ```
 
 Aliased as `res.contentType(type)`.