Use form mixin for add field change handler

js/mixins/form.js

@@ -0,0 +1,14 @@
+export default {
+  mounted: function () {
+    this.$root.$on('field-change', this.handleFieldChange)
+  },
+
+  methods: {
+    handleFieldChange: function (event) {
+      const { value, name } = event
+      if (typeof this[name] !== undefined) {
+        this[name] = value
+      }
+    },
+  }
+}