fix(exe): use runtime semver check for ESM SEA default format

sxzz · sxzz · commit 5321c8a69817 · 2026-02-26T14:42:26.000+09:00
Instead of always defaulting to CJS when exe is enabled, check the
Node.js version at runtime to determine ESM SEA support (&gt;= v25.7.0).
diff --git a/docs/reference/cli.md b/docs/reference/cli.md
@@ -254,7 +254,7 @@ This will bundle the output into a single executable file using Node.js SEA. Req
 
 When `exe` is enabled:
 
-- The default output format changes from `esm` to `cjs` (unless ESM SEA is supported).
+- The default output format changes from `esm` to `cjs` (unless ESM SEA is supported, i.e., Node.js >= v25.7.0).
 - Declaration file generation (`dts`) is disabled by default.
 - Code splitting is disabled.
 - Only single entry points are supported.
diff --git a/docs/zh-CN/reference/cli.md b/docs/zh-CN/reference/cli.md
@@ -254,7 +254,7 @@ tsdown --copy public
 
 启用 `exe` 时：
 
-- 默认输出格式从 `esm` 变更为 `cjs`（除非支持 ESM SEA）。
+- 默认输出格式从 `esm` 变更为 `cjs`（除非支持 ESM SEA，即 Node.js >= v25.7.0）。
 - 默认禁用声明文件生成（`dts`）。
 - 禁用代码分割。
 - 仅支持单入口。
diff --git a/src/config/options.ts b/src/config/options.ts
@@ -1,3 +1,4 @@
+import satisfies from 'semver/functions/satisfies.js'
 import { readFile } from 'node:fs/promises'
 import path from 'node:path'
 import process from 'node:process'
@@ -290,14 +291,18 @@ export async function resolveUserConfig(
     write,
   }
 
+  let defaultFormat: Format = 'esm'
   if (exe) {
     validateSea(config)
+    if (satisfies(process.version, '<25.7.0')) {
+      defaultFormat = 'cjs'
+    }
   }
 
   const objectFormat = typeof format === 'object' && !Array.isArray(format)
   const formats = objectFormat
     ? (Object.keys(format) as Format[])
-    : resolveComma(toArray<Format>(format, exe ? 'cjs' : 'es'))
+    : resolveComma(toArray<Format>(format, defaultFormat))
 
   return formats.map((fmt, idx): ResolvedConfig => {
     const once = idx === 0
diff --git a/src/config/types.ts b/src/config/types.ts
@@ -329,11 +329,17 @@ export interface UserConfig {
   //#region Output Options
 
   /**
-   * Output format(s). Defaults to ESM.
+   * Output format(s). Available formats are
+   * - `esm`: ESM
+   * - `cjs`: CommonJS
+   * - `iife`: IIFE
+   * - `umd`: UMD
+   *
+   * Defaults to ESM.
    *
    * ### Usage with {@link exe}
    * If `exe` is enabled, the default format will depend on support level of SEA in the target Node.js version:
-   * - If ESM SEA is supported, the default format will be ESM.
+   * - If ESM SEA is supported (Node.js > v25.7), the default format will be ESM.
    * - If only CJS SEA is supported, the default format will be CJS.
    */
   format?: Format | Format[] | Partial<Record<Format, Partial<ResolvedConfig>>>
