feat: export mergeConfig

Author: sxzz

dts.snapshot.json

@@ -1,14 +1,18 @@
 {
-  "config.d.mts": {
+  "config-!~{00e}~.d.mts": {
     "defineConfig": "declare function defineConfig(_: UserConfigExport): UserConfigExport",
+    "mergeConfig": "declare function mergeConfig(_: InlineConfig, _: InlineConfig): InlineConfig"
+  },
+  "config.d.mts": {
     "#exports": [
       "UserConfig",
       "UserConfigExport",
       "UserConfigFn",
-      "defineConfig"
+      "defineConfig",
+      "mergeConfig"
     ]
   },
-  "index-!~{00a}~.d.mts": {
+  "index-!~{00c}~.d.mts": {
     "Arrayable": "type Arrayable<T> = T | T[]",
     "AttwOptions": "interface AttwOptions extends CheckPackageOptions {\n profile?: 'strict' | 'node16' | 'esm-only'\n level?: 'error' | 'warn'\n ignoreRules?: string[]\n}",
     "Awaitable": "type Awaitable<T> = T | Promise<T>",
@@ -111,7 +115,8 @@
       "Workspace",
       "build",
       "defineConfig",
-      "globalLogger"
+      "globalLogger",
+      "mergeConfig"
     ]
   },
   "plugins.d.mts": {

src/config.ts

@@ -3,7 +3,6 @@ import type {
   UserConfigExport,
   UserConfigFn,
 } from './config/index.ts'
-
 /**
  * Defines the configuration for tsdown.
  */
@@ -16,3 +15,4 @@ export function defineConfig(options: UserConfigExport): UserConfigExport {
 }
 
 export type { UserConfig, UserConfigExport, UserConfigFn }
+export { mergeConfig } from './config/options.ts'

src/config/options.test.ts

@@ -1,6 +1,9 @@
 import isInCi from 'is-in-ci'
 import { describe, expect, test } from 'vitest'
-import { resolveFeatureOption as _resolveFeatureOption } from './options.ts'
+import {
+  resolveFeatureOption as _resolveFeatureOption,
+  mergeConfig,
+} from './options.ts'
 
 const defaultOption = { a: 1 }
 interface DefaultOption {
@@ -55,3 +58,33 @@ describe('resolveFeatureOption', () => {
     }
   })
 })
+
+test('mergeConfig', () => {
+  expect(
+    mergeConfig(
+      {
+        a: 1,
+        obj: { c: 2, d: 3 },
+        arr: [1, 2, 3],
+      } as any,
+      {
+        obj: { c: 42 },
+        arr: [4, 5],
+        e: 5,
+      } as any,
+    ),
+  ).toMatchInlineSnapshot(`
+    {
+      "a": 1,
+      "arr": [
+        4,
+        5,
+      ],
+      "e": 5,
+      "obj": {
+        "c": 42,
+        "d": 3,
+      },
+    }
+  `)
+})

src/config/options.ts

@@ -335,6 +335,21 @@ const defu = createDefu((obj, key, value) => {
   }
 })
 
+export function mergeConfig(
+  defaults: UserConfig,
+  overrides: UserConfig,
+): UserConfig
+export function mergeConfig(
+  defaults: InlineConfig,
+  overrides: InlineConfig,
+): InlineConfig
+export function mergeConfig(
+  defaults: InlineConfig,
+  overrides: InlineConfig,
+): InlineConfig {
+  return defu(overrides, defaults)
+}
+
 export async function mergeUserOptions<T extends object, A extends unknown[]>(
   defaults: T,
   user:

src/index.ts

@@ -298,7 +298,7 @@ const pkgRoot: string = path.resolve(dirname, '..')
 /** @internal */
 export const shimFile: string = path.resolve(pkgRoot, 'esm-shims.js')
 
-export { defineConfig } from './config.ts'
+export { defineConfig, mergeConfig } from './config.ts'
 export * from './config/types.ts'
 export { globalLogger, type Logger } from './utils/logger.ts'
 export * as Rolldown from 'rolldown'