feat: add getLayerModuleOptions

Author: BobbieGoede

README.md

@@ -34,6 +34,39 @@ export default defineNuxtModule({
 })
 ```
 
+### `getLayerModuleOptions<T>(layer: NuxtConfigLayer, configKey: string, name: string)`
+
+Get module options from a given Nuxt layer.
+
+This takes into account both inline module options specified in the `modules` array and options specified in the layer's config under a specific key. It returns the merged options if both are configured, or the first available option.
+
+```ts
+// src/module.ts
+import { defineNuxtModule } from '@nuxt/kit'
+import { getLayerModuleOptions } from 'nuxt-module-utils'
+
+export interface ModuleOptions {
+  myOption?: string
+}
+
+export default defineNuxtModule<ModuleOptions>({
+  meta: {
+    name: 'my-module',
+    configKey: 'myModule', // key in nuxt.config
+  },
+  async setup(options, nuxt) {
+    for (const layer of nuxt.options._layers) {
+      const layerModuleOptions = getLayerModuleOptions(
+        layer,
+        'myModule', // key in nuxt.config
+        'my-module' // name in modules array
+      )
+      // ...
+    }
+  }
+})
+```
+
 ## Sponsors
 
 <p align="center">

src/index.ts

@@ -1 +1,2 @@
 export { hoistDependencies } from "./hoist";
+export { getLayerModuleOptions } from "./layers";

src/layers.ts

@@ -0,0 +1,47 @@
+import type { NuxtConfigLayer } from "@nuxt/schema";
+import { defu } from "defu";
+
+type GetModuleOptions<
+  T,
+  K extends keyof NuxtConfigLayer["config"],
+> = [T] extends [never] ? NuxtConfigLayer["config"][K] : T;
+
+/**
+ * Get module options from a given Nuxt layer
+ *
+ * This takes into account both inline module options specified in the `modules` array
+ * and options specified in the layer's config under a specific key.
+ *
+ * Returns the merged options if both are provided, or the first available option.
+ *
+ * @param layer - a {@link NuxtConfigLayer | Nuxt Layer} from `nuxt.options._layers`
+ * @param configKey - the key used to configure module options in nuxt.config
+ * @param name - the module name as it would be specified in the `modules` array
+ * @returns
+ */
+export function getLayerModuleOptions<
+  T = never,
+  K extends keyof NuxtConfigLayer["config"] = keyof NuxtConfigLayer["config"],
+>(
+  layer: NuxtConfigLayer,
+  configKey: K,
+  name: string,
+): GetModuleOptions<T, K> | undefined {
+  type Options = GetModuleOptions<T, K>;
+
+  const matchInlineOptions = (mod: any): mod is [string, Options] =>
+    Array.isArray(mod) && typeof mod[0] === "string" && mod[0] === name;
+
+  const modules = (layer.config.modules || []) as [
+    string,
+    unknown | undefined,
+  ][];
+  const inlineOptions = modules.find(matchInlineOptions)?.[1];
+  const keyOptions = layer.config[configKey] as Options | undefined;
+
+  if (inlineOptions == null && keyOptions == null) {
+    return undefined;
+  }
+
+  return defu(keyOptions || {}, inlineOptions || {}) as Options;
+}