add nova

nova/resources/js/mixins/HandlesPanelVisibility.js

@@ -0,0 +1,36 @@
+import each from 'lodash/each'
+import filter from 'lodash/filter'
+
+export default {
+  emits: ['field-shown', 'field-hidden'],
+
+  data: () => ({
+    visibleFieldsForPanel: {},
+  }),
+
+  created() {
+    each(this.panel.fields, field => {
+      this.visibleFieldsForPanel[field.attribute] = field.visible
+    })
+  },
+
+  methods: {
+    handleFieldShown(field) {
+      this.visibleFieldsForPanel[field] = true
+      this.$emit('field-shown', field)
+    },
+
+    handleFieldHidden(field) {
+      this.visibleFieldsForPanel[field] = false
+      this.$emit('field-hidden', field)
+    },
+  },
+
+  computed: {
+    visibleFieldsCount() {
+      return Object.entries(
+        filter(this.visibleFieldsForPanel, visible => visible === true)
+      ).length
+    },
+  },
+}