feat: 优化支付宝小程序下的countdown倒计时性能，减少setData数据量（去除无用的data）。

packages/rax-countdown/CHANGELOG.md

@@ -1,4 +1,7 @@
 # Changelog
+## v1.2.1
+
+- Feat decrease setData data size for promote performance
 
 ## v1.2.0
 

packages/rax-countdown/package.json

@@ -1,6 +1,6 @@
 {
   "name": "rax-countdown",
-  "version": "1.2.0",
+  "version": "1.2.1",
   "description": "Countdown component for Rax.",
   "license": "BSD-3-Clause",
   "main": "lib/index.js",

packages/rax-countdown/src/miniapp-native/ali-miniapp/index.ts

@@ -88,11 +88,14 @@ Component({
           case 'm':
           case 's':
             if (index % 2 === 0) {
-              // insert plain text before current matched item
-              return {
-                value: tpl.slice(lastPlaintextIndex, val),
-                style: textStyle
-              };
+              const value = tpl.slice(lastPlaintextIndex, val);
+              if (value || textStyle) {
+                  // insert plain text before current matched item
+                return {
+                  value,
+                  style: textStyle
+                };
+              }
             } else {
               // replace current matched item to realtime string
               lastPlaintextIndex = val + 3;