fix(mp): v-model support dynamic add reactive properties

packages/vue-cli-plugin-uni/packages/mp-vue/dist/mp.runtime.esm.js

@@ -4087,10 +4087,10 @@ function updateChildComponent (
     // keep a copy of raw propsData
     vm.$options.propsData = propsData;
   }
-  
+
   // fixed by xxxxxx update properties(mp runtime)
   vm._$updateProperties && vm._$updateProperties(vm);
-  
+
   // update listeners
   listeners = listeners || emptyObject;
   var oldListeners = vm.$options._parentListeners;
@@ -4621,7 +4621,7 @@ function initProps (vm, propsOptions) {
             }
             //fixed by xxxxxx __next_tick_pending,uni://form-field 时不告警
             if(
-                key === 'value' && 
+                key === 'value' &&
                 Array.isArray(vm.$options.behaviors) &&
                 vm.$options.behaviors.indexOf('uni://form-field') !== -1
               ){
@@ -4633,7 +4633,7 @@ function initProps (vm, propsOptions) {
             var $parent = vm.$parent;
             while($parent){
               if($parent.__next_tick_pending){
-                return  
+                return
               }
               $parent = $parent.$parent;
             }
@@ -4965,10 +4965,10 @@ function initMixin (Vue) {
     initEvents(vm);
     initRender(vm);
     callHook(vm, 'beforeCreate');
-    !vm._$fallback && initInjections(vm); // resolve injections before data/props  
+    !vm._$fallback && initInjections(vm); // resolve injections before data/props
     initState(vm);
     !vm._$fallback && initProvide(vm); // resolve provide after data/props
-    !vm._$fallback && callHook(vm, 'created');      
+    !vm._$fallback && callHook(vm, 'created');
 
     /* istanbul ignore if */
     if (process.env.NODE_ENV !== 'production' && config.performance && mark) {
@@ -5694,7 +5694,7 @@ function mountComponent$1(
       }
     }
   }
-  
+
   !vm._$fallback && callHook(vm, 'beforeMount');
 
   var updateComponent = function () {
@@ -5893,14 +5893,16 @@ function internalMixin(Vue) {
     if (!target) {
       target = this;
     }
-    target[key] = value;
+    // 解决动态属性添加
+    Vue.set(target, key, value)
   };
 
   Vue.prototype.__set_sync = function(target, key, value) {
     if (!target) {
       target = this;
     }
-    target[key] = value;
+    // 解决动态属性添加
+    Vue.set(target, key, value)
   };
 
   Vue.prototype.__get_orig = function(item) {
@@ -6033,7 +6035,7 @@ Vue.prototype.__patch__ = patch;
 // public mount method
 Vue.prototype.$mount = function(
     el ,
-    hydrating 
+    hydrating
 ) {
     return mountComponent$1(this, el, hydrating)
 };