diff --git a/package.json b/package.json
index 6a2e5a7..7ac78a4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@bd/core",
-  "version": "1.2.2",
+  "version": "1.3.0",
   "type": "module",
   "description": "百搭UI组件库的核心",
   "main": "dist/index.js",
diff --git a/src/constants.js b/src/constants.js
index f18f792..8fd992c 100644
--- a/src/constants.js
+++ b/src/constants.js
@@ -120,7 +120,9 @@ export function parsePropsDeclaration(options) {
       options = getType(options)
       break
   }
-  options.default = options.default || getDefaultValue(options.type)
+  options.default = options.hasOwnProperty('default')
+    ? options.default
+    : getDefaultValue(options.type)
   options.attribute = true
   return options
 }
@@ -128,7 +130,7 @@ export function parsePropsDeclaration(options) {
 export function fixedValue(value, options) {
   switch (options.type) {
     case Number:
-      return +value || 0
+      return value === null ? null : +value || 0
       break
 
     case Boolean:
@@ -160,7 +162,7 @@ export function fixedValue(value, options) {
       break
 
     default:
-      return value + ''
+      return value === null ? null : value + ''
       break
   }
 }
diff --git a/src/index.js b/src/index.js
index db70be2..06a3cdd 100644
--- a/src/index.js
+++ b/src/index.js
@@ -56,6 +56,9 @@ export class Component extends HTMLElement {
           return
         }
         this[key] = value
+        if (options.observer) {
+          options.observer.call(this, value, oldValue)
+        }
         this.#requestUpdate(name, oldValue)
       },
       enumerable: false