feat(exports): add bin option to auto-generate package.json bin field

dts.snapshot.json

@@ -1,7 +1,7 @@
 {
   "config-!~{00d}~.d.mts": {
     "defineConfig": "declare function defineConfig(_: UserConfigExport): UserConfigExport",
-    "mergeConfig": "declare function mergeConfig(_: InlineConfig, _: InlineConfig): InlineConfig",
+    "mergeConfig": "declare function mergeConfig(_: InlineConfig, ...overrides: InlineConfig[]): InlineConfig",
     "resolveUserConfig": "declare function resolveUserConfig(_: UserConfig, _: InlineConfig): Promise<ResolvedConfig[]>"
   },
   "config.d.mts": {
@@ -128,7 +128,7 @@
     "DepsPlugin": "declare function DepsPlugin(_: ResolvedConfig, _: TsdownBundle): Plugin",
     "DevtoolsOptions": "interface DevtoolsOptions extends NonNullable<InputOptions['devtools']> {\n ui?: boolean | Partial<StartOptions>\n clean?: boolean\n}",
     "ExeOptions": "interface ExeOptions extends ExeExtensionOptions {\n seaConfig?: Omit<SeaConfig, 'main' | 'output' | 'mainFormat'>\n fileName?: string | ((_: RolldownChunk) => string)\n outDir?: string\n}",
-    "ExportsOptions": "interface ExportsOptions {\n devExports?: boolean | string\n packageJson?: boolean\n all?: boolean\n exclude?: (RegExp | string)[]\n legacy?: boolean\n customExports?: Record<string, any> | ((_: Record<string, any>, _: { pkg: PackageJson; chunks: ChunksByFormat; isPublish: boolean }) => Awaitable<Record<string, any>>)\n inlinedDependencies?: boolean\n}",
+    "ExportsOptions": "interface ExportsOptions {\n devExports?: boolean | string\n packageJson?: boolean\n all?: boolean\n exclude?: (RegExp | string)[]\n legacy?: boolean\n customExports?: Record<string, any> | ((_: Record<string, any>, _: { pkg: PackageJson; chunks: ChunksByFormat; isPublish: boolean }) => Awaitable<Record<string, any>>)\n inlinedDependencies?: boolean\n bin?: boolean | string | Record<string, string>\n}",
     "Format": "type Format = ModuleFormat",
     "InlineConfig": "interface InlineConfig extends UserConfig {\n config?: boolean | string\n configLoader?: 'auto' | 'native' | 'unrun'\n filter?: RegExp | Arrayable<string>\n}",
     "NoExternalFn": "type NoExternalFn = (_: string, _: string | undefined) => boolean | null | undefined | void",

packages/create-tsdown/tsdown.config.ts

@@ -2,4 +2,7 @@ import type { UserConfig } from '../../src/config.ts'
 
 export default {
   entry: ['./src/{index,run}.ts'],
+  exports: {
+    bin: true,
+  },
 } satisfies UserConfig

packages/migrate/tsdown.config.ts

@@ -3,4 +3,7 @@ import type { UserConfig } from '../../src/config.ts'
 export default {
   name: 'migrate',
   entry: ['./src/{index,run}.ts'],
+  exports: {
+    bin: true,
+  },
 } satisfies UserConfig

src/config/options.ts

@@ -361,17 +361,21 @@ const defu = createDefu((obj, key, value) => {
 
 export function mergeConfig(
   defaults: UserConfig,
-  overrides: UserConfig,
+  ...overrides: UserConfig[]
 ): UserConfig
 export function mergeConfig(
   defaults: InlineConfig,
-  overrides: InlineConfig,
+  ...overrides: InlineConfig[]
 ): InlineConfig
 export function mergeConfig(
   defaults: InlineConfig,
-  overrides: InlineConfig,
+  ...overrides: InlineConfig[]
 ): InlineConfig {
-  return defu(overrides, defaults)
+  return defu(
+    // @ts-expect-error - defu does not handle overloads well
+    ...overrides.toReversed(),
+    defaults,
+  )
 }
 
 export async function mergeUserOptions<T extends object, A extends unknown[]>(

src/config/workspace.ts

@@ -4,6 +4,7 @@ import { createDebug } from 'obug'
 import { glob } from 'tinyglobby'
 import { slash } from '../utils/general.ts'
 import { loadConfigFile } from './file.ts'
+import { mergeConfig } from './options.ts'
 import type { InlineConfig, UserConfig } from './types.ts'
 
 const debug = createDebug('tsdown:config:workspace')
@@ -19,7 +20,7 @@ export async function resolveWorkspace(
   config: UserConfig,
   inlineConfig: InlineConfig,
 ): Promise<{ configs: UserConfig[]; files?: string[] }> {
-  const normalized: UserConfig = { ...config, ...inlineConfig }
+  const normalized = mergeConfig(config, inlineConfig)
   const rootCwd = normalized.cwd || process.cwd()
 
   let { workspace } = normalized
@@ -82,9 +83,7 @@ export async function resolveWorkspace(
         } else {
           debug('no workspace config file found in %s', cwd)
         }
-        return configs.map(
-          (config): UserConfig => ({ ...normalized, ...config }),
-        )
+        return configs.map((config) => mergeConfig(normalized, config))
       }),
     )
   ).flat()