fix(Picker): should watch columns change (#5614)

src/picker/PickerColumn.js

@@ -73,6 +73,8 @@ export default createComponent({
   },
 
   watch: {
+    initialOptions: 'setOptions',
+
     defaultIndex(val) {
       this.setIndex(val);
     },
@@ -89,6 +91,13 @@ export default createComponent({
   },
 
   methods: {
+    setOptions(options) {
+      if (JSON.stringify(options) !== JSON.stringify(this.options)) {
+        this.options = deepClone(options);
+        this.setIndex(this.defaultIndex);
+      }
+    },
+
     onTouchStart(event) {
       this.touchStart(event);
 

src/picker/index.js

@@ -182,12 +182,9 @@ export default createComponent({
     // set options of column by index
     setColumnValues(index, options) {
       const column = this.children[index];
-      if (
-        column &&
-        JSON.stringify(column.options) !== JSON.stringify(options)
-      ) {
-        column.options = options;
-        column.setIndex(0);
+
+      if (column) {
+        column.setOptions(options);
       }
     },
 

src/picker/test/index.spec.js

@@ -262,3 +262,37 @@ test('cascade columns', () => {
     'Gulou',
   ]);
 });
+
+test('watch columns change', () => {
+  const wrapper = mount(Picker, {
+    propsData: {
+      showToolbar: true,
+      columns: ['1', '2'],
+      defaultIndex: 1,
+    },
+  });
+
+  wrapper.setProps({
+    columns: ['2', '3'],
+  });
+
+  wrapper.find('.van-picker__confirm').trigger('click');
+  expect(wrapper.emitted('confirm')[0]).toEqual(['3', 1]);
+});
+
+test('should not reset index when columns unchanged', () => {
+  const wrapper = mount(Picker, {
+    propsData: {
+      showToolbar: true,
+      columns: ['1', '2'],
+    },
+  });
+
+  wrapper.vm.setIndexes([1]);
+  wrapper.setProps({
+    columns: ['1', '2'],
+  });
+
+  wrapper.find('.van-picker__confirm').trigger('click');
+  expect(wrapper.emitted('confirm')[0]).toEqual(['2', 1]);
+});