feat: add unrun as a config loader (#563)

Co-authored-by: Kevin Deng <[email protected]>

Author: Gugustinette

docs/options/config-file.md

@@ -69,9 +69,10 @@ This is useful if you want to rely solely on command-line options or default set
 - `auto` (default): Utilizes native runtime loading for TypeScript if supported; otherwise, defaults to `unconfig`.
 - `native`: Loads TypeScript configuration files using native runtime support. Requires a compatible environment, such as the latest Node.js, Deno, or Bun.
 - `unconfig`: Loads configuration files with the `unconfig` library, ensuring broad compatibility across different runtimes.
+- `unrun` _(experimental)_: Loads configuration files using the [`unrun`](https://gugustinette.github.io/unrun/) library, which provides similar compatibility as `unconfig` but with more performances.
 
 > [!TIP]
-> Node.js does not natively support importing TypeScript files without specifying the file extension. If you are using Node.js and want to load a TypeScript config file without including the `.ts` extension, consider using the `unconfig` loader for seamless compatibility.
+> Node.js does not natively support importing TypeScript files without specifying the file extension. If you are using Node.js and want to load a TypeScript config file without including the `.ts` extension, consider using the `unconfig` or `unrun` loader for seamless compatibility.
 
 ## Extending Vite or Vitest Config (Experimental)
 

docs/zh-CN/options/config-file.md

@@ -69,9 +69,10 @@ tsdown --no-config
 - `auto`（默认）：如果运行时支持，则使用原生方式加载 TypeScript，否则回退到 `unconfig`。
 - `native`：通过原生运行时支持加载 TypeScript 配置文件。需要兼容的环境，如最新版 Node.js、Deno 或 Bun。
 - `unconfig`：使用 `unconfig` 库加载配置文件，确保在不同运行时下具有广泛兼容性。
+- `unrun` _(experimental)_: Loads configuration files using the [`unrun`](https://gugustinette.github.io/unrun/) library, which provides similar compatibility as `unconfig` but with more performances.
 
 > [!TIP]
-> Node.js 原生不支持在不指定文件扩展名的情况下导入 TypeScript 文件。如果您在 Node.js 环境下希望加载不带 `.ts` 扩展名的 TypeScript 配置文件，建议使用 `unconfig` 加载器以获得更好的兼容性。
+> Node.js 原生不支持在不指定文件扩展名的情况下导入 TypeScript 文件。如果您在 Node.js 环境下希望加载不带 `.ts` 扩展名的 TypeScript 配置文件，建议使用 `unconfig` 或 `unrun` 加载器以获得更好的兼容性。
 
 ## 扩展 Vite 或 Vitest 配置（实验性功能）{#extending-vite-or-vitest-config-experimental}
 

package.json

@@ -48,8 +48,8 @@
   "scripts": {
     "lint": "eslint --cache --max-warnings 0 .",
     "lint:fix": "pnpm run lint --fix",
-    "build": "tsx ./src/run.ts",
-    "dev": "tsx ./src/run.ts",
+    "build": "unrun ./src/run.ts",
+    "dev": "unrun ./src/run.ts",
     "test": "vitest",
     "typecheck": "tsc --noEmit",
     "format": "prettier --cache --write .",
@@ -98,7 +98,8 @@
     "tinyexec": "catalog:prod",
     "tinyglobby": "catalog:prod",
     "tree-kill": "catalog:prod",
-    "unconfig": "catalog:prod"
+    "unconfig": "catalog:prod",
+    "unrun": "catalog:prod"
   },
   "devDependencies": {
     "@arethetypeswrong/core": "catalog:dev",
@@ -117,7 +118,6 @@
     "prettier": "catalog:dev",
     "publint": "catalog:dev",
     "rolldown-plugin-require-cjs": "catalog:dev",
-    "tsx": "catalog:dev",
     "typescript": "catalog:dev",
     "unocss": "catalog:docs",
     "unplugin-lightningcss": "catalog:dev",

pnpm-lock.yaml

@@ -22,7 +22,6 @@ catalogs:
     prettier: ^3.6.2
     publint: ^0.3.15
     rolldown-plugin-require-cjs: ^0.3.1
-    tsx: ^4.20.6
     typescript: ~5.9.3
     unplugin-lightningcss: ^0.4.3
     unplugin-unused: ^0.5.4
@@ -62,6 +61,7 @@ catalogs:
     tinyglobby: ^0.2.15
     tree-kill: ^1.2.2
     unconfig: ^7.3.3
+    unrun: ^0.2.0
 
 ignoredBuiltDependencies:
   - rolldown

pnpm-workspace.yaml

@@ -3,6 +3,7 @@ import process from 'node:process'
 import { pathToFileURL } from 'node:url'
 import { underline } from 'ansis'
 import { loadConfig } from 'unconfig'
+import { unrun } from 'unrun'
 import { fsStat } from '../utils/fs'
 import { toArray } from '../utils/general'
 import { globalLogger } from '../utils/logger'
@@ -98,7 +99,12 @@ export async function loadConfigFile(
             {
               files: 'tsdown.config',
               extensions: ['ts', 'mts', 'cts', 'js', 'mjs', 'cjs', 'json', ''],
-              parser: isNative ? nativeImport : 'auto',
+              parser:
+                options.configLoader === 'unrun'
+                  ? unrunImport
+                  : isNative
+                    ? nativeImport
+                    : 'auto',
             },
             {
               files: 'package.json',
@@ -146,3 +152,21 @@ async function nativeImport(id: string) {
   const config = mod.default || mod
   return config
 }
+
+async function unrunImport(id: string) {
+  const { module } = await unrun({
+    path: pathToFileURL(id).href,
+  }).catch((error) => {
+    const cannotFindModule = error?.message?.includes?.('Cannot find module')
+    if (cannotFindModule) {
+      const configError = new Error(
+        `Failed to load the config file. \`unrun\` is experimental; try setting the --config-loader CLI flag to \`unconfig\` instead.\n\n${error.message}`,
+      )
+      configError.cause = error
+      throw configError
+    } else {
+      throw error
+    }
+  })
+  return module
+}

src/options/config.ts

@@ -361,7 +361,7 @@ export interface Options {
    * Config loader to use. It can only be set via CLI or API.
    * @default 'auto'
    */
-  configLoader?: 'auto' | 'native' | 'unconfig'
+  configLoader?: 'auto' | 'native' | 'unconfig' | 'unrun'
 
   /**
    * Reuse config from Vite or Vitest (experimental)