diff --git a/coretool.js b/coretool.js
index 03ca2c4..01a5edf 100644
--- a/coretool.js
+++ b/coretool.js
@@ -1,6 +1,9 @@
 /* 基础小工具，可通用于服务端和用户端
  */
 
+const path = require('path')
+const fs = require('fs')
+
 module.exports = {
   BASEPORT_API_SERVER: 7000,
   BASEPORT_WEB_SERVER: 8000,
@@ -359,6 +362,18 @@ module.exports = {
     delete file.filename
     delete file.destination
     return file
-  }
+  },
+
+  has_module (module) {
+    if (typeof (module) === 'string' && module) {
+      return module.paths.some(modulesPath => fs.existsSync(path.join(modulesPath, module)))
+    } else {
+      return false
+    }
+  },
+
+  segment_number (sizeBytes = '') { // segment a number with a space between each 3 digits
+    return (sizeBytes).toString().replace(/\B(?=(\d{3})+(?!\d))/g, ' ')
+  },
 
 }