[Improvement] optimize find parent mixin (#781)

packages/collapse/index.vue

@@ -10,13 +10,9 @@ import create from '../utils/create';
 export default create({
   name: 'collapse',
 
-  model: {
-    prop: 'activeNames'
-  },
-
   props: {
     accordion: Boolean,
-    activeNames: [String, Number, Array]
+    value: [String, Number, Array]
   },
 
   data() {
@@ -27,11 +23,10 @@ export default create({
 
   methods: {
     switch(name, expanded) {
-      const { activeNames } = this;
       if (!this.accordion) {
         name = expanded
-          ? activeNames.concat(name)
-          : activeNames.filter(activeName => activeName !== name);
+          ? this.value.concat(name)
+          : this.value.filter(activeName => activeName !== name);
       }
       this.$emit('change', name);
       this.$emit('input', name);