Support (async) function in vite plugin (resolves #303)

src/plugins/vite/index.ts

@@ -1,7 +1,7 @@
 import { timerify } from '../../util/Performance.js';
 import { hasDependency, load } from '../../util/plugin.js';
 import { findVitestDeps } from '../vitest/index.js';
-import type { ViteConfig } from './types.js';
+import type { ViteConfig, MODE, COMMAND } from './types.js';
 import type { IsPluginEnabledCallback, GenericPluginCallback } from '../../types/plugins.js';
 
 // https://vitejs.dev/config/
@@ -20,6 +20,17 @@ const findViteDependencies: GenericPluginCallback = async (configFilePath, optio
 
   if (!localConfig) return [];
 
+  if (typeof localConfig === 'function') {
+    const dependencies = new Set<string>();
+    for (const command of ['dev', 'serve', 'build'] as COMMAND[]) {
+      for (const mode of ['development', 'production'] as MODE[]) {
+        const config = await localConfig({ command, mode, ssrBuild: undefined });
+        findVitestDeps(config, options).forEach(dependency => dependencies.add(dependency));
+      }
+    }
+    return Array.from(dependencies);
+  }
+
   return findVitestDeps(localConfig, options);
 };
 

src/plugins/vite/types.ts

@@ -1,5 +1,16 @@
 import type { VitestConfig } from '../vitest/types.js';
 
-export interface ViteConfig extends VitestConfig {
+interface Config extends VitestConfig {
   plugins: unknown[];
 }
+
+export type COMMAND = 'dev' | 'serve' | 'build';
+export type MODE = 'development' | 'production';
+
+interface Options {
+  command: COMMAND;
+  mode: MODE;
+  ssrBuild?: boolean | undefined;
+}
+
+export type ViteConfig = Config | ((options: Options) => Config) | ((options: Options) => Promise<Config>);