fix(types): add more overload to defineConfig (vitejs#18299)

packages/vite/src/node/__tests_dts__/config.ts

@@ -0,0 +1,47 @@
+/* eslint-disable @typescript-eslint/ban-ts-comment */
+/* eslint-disable @typescript-eslint/no-unused-vars */
+import type { Equal, ExpectTrue } from '@type-challenges/utils'
+import {
+  type UserConfig,
+  type UserConfigExport,
+  type UserConfigFn,
+  type UserConfigFnObject,
+  type UserConfigFnPromise,
+  defineConfig,
+} from '../config'
+import { mergeConfig } from '../publicUtils'
+
+const configObjectDefined = defineConfig({})
+const configObjectPromiseDefined = defineConfig(Promise.resolve({}))
+const configFnObjectDefined = defineConfig(() => ({}))
+const configFnPromiseDefined = defineConfig(async () => ({}))
+const configFnDefined = defineConfig(() =>
+  // TypeScript requires both non-promise config and
+  // promise config to have at least one property
+  Math.random() > 0.5 ? { base: '' } : Promise.resolve({ base: '/' }),
+)
+const configExportDefined = defineConfig({} as UserConfigExport)
+
+export type cases1 = [
+  ExpectTrue<Equal<typeof configObjectDefined, UserConfig>>,
+  ExpectTrue<Equal<typeof configObjectPromiseDefined, Promise<UserConfig>>>,
+  ExpectTrue<Equal<typeof configFnObjectDefined, UserConfigFnObject>>,
+  ExpectTrue<Equal<typeof configFnPromiseDefined, UserConfigFnPromise>>,
+  ExpectTrue<Equal<typeof configFnDefined, UserConfigFn>>,
+  ExpectTrue<Equal<typeof configExportDefined, UserConfigExport>>,
+]
+
+defineConfig({
+  base: '',
+  // @ts-expect-error
+  unknownProperty: 1,
+})
+
+mergeConfig(defineConfig({}), defineConfig({}))
+mergeConfig(
+  // @ts-expect-error
+  defineConfig(() => ({})),
+  defineConfig({}),
+)
+
+export {}

packages/vite/src/node/config.ts

@@ -131,6 +131,8 @@ export type UserConfigExport =
 export function defineConfig(config: UserConfig): UserConfig
 export function defineConfig(config: Promise<UserConfig>): Promise<UserConfig>
 export function defineConfig(config: UserConfigFnObject): UserConfigFnObject
+export function defineConfig(config: UserConfigFnPromise): UserConfigFnPromise
+export function defineConfig(config: UserConfigFn): UserConfigFn
 export function defineConfig(config: UserConfigExport): UserConfigExport
 export function defineConfig(config: UserConfigExport): UserConfigExport {
   return config