feat(kit): add extendRouteRules method (#9771)

docs/content/1.docs/3.api/4.advanced/2.kit.md

@@ -61,6 +61,7 @@ description: Nuxt Kit provides composable utilities to help interacting with Nux
 [source code](https://github.com/nuxt/nuxt/blob/main/packages/kit/src/pages.ts)
 
 - `extendPages (callback: pages => void)`
+- `extendRouteRules (route: string, rule: NitroRouteConfig, options: ExtendRouteRulesOptions)`
 
 ### Plugins
 

packages/kit/src/pages.ts

@@ -1,4 +1,6 @@
 import type { NuxtHooks } from '@nuxt/schema'
+import type { NitroRouteConfig } from 'nitropack'
+import { defu } from 'defu'
 import { useNuxt } from './context'
 import { isNuxt2 } from './compatibility'
 
@@ -11,3 +13,24 @@ export function extendPages (cb: NuxtHooks['pages:extend']) {
     nuxt.hook('pages:extend', cb)
   }
 }
+
+export interface ExtendRouteRulesOptions {
+  /**
+   * Override route rule config
+   *
+   * @default false
+   */
+  override?: boolean
+}
+
+export function extendRouteRules (route: string, rule: NitroRouteConfig, options: ExtendRouteRulesOptions = {}) {
+  const nuxt = useNuxt()
+  for (const opts of [nuxt.options, nuxt.options.nitro]) {
+    if (!opts.routeRules) {
+      opts.routeRules = {}
+    }
+    opts.routeRules[route] = options.override
+      ? defu(rule, opts.routeRules[route])
+      : defu(opts.routeRules[route], rule)
+  }
+}