fix(Field): correctly limit maxlength when pasting multiple emojis (#13713)

packages/vant/src/field/Field.tsx

@@ -308,10 +308,11 @@ export default defineComponent({
         }
         // Remove redundant interpolated values,
         // make it consistent with the native input maxlength behavior.
-        const selectionEnd = inputRef.value?.selectionEnd;
+        let selectionEnd = inputRef.value?.selectionEnd;
         if (state.focused && selectionEnd) {
           const valueArr = [...value];
           const exceededLength = valueArr.length - +maxlength;
+          selectionEnd = getStringLength(value.slice(0, selectionEnd));
           valueArr.splice(selectionEnd - exceededLength, exceededLength);
           return valueArr.join('');
         }

packages/vant/src/field/test/index.spec.js

@@ -644,3 +644,22 @@ test('should update selection range correctly when using formatter with emoji',
 
   expect(input.element.selectionEnd).toEqual(4);
 });
+
+test('should limit maxlength correctly when pasting multiple emojis', async () => {
+  const wrapper = mount(Field, {
+    props: {
+      maxlength: 4,
+      modelValue: '',
+    },
+  });
+
+  const input = wrapper.find('input');
+  await input.trigger('focus');
+
+  input.element.value = '1😀😀😀😀';
+  input.element.selectionEnd = 9;
+  input.trigger('input');
+
+  expect(wrapper.emitted('update:modelValue')[0][0]).toEqual('1😀😀😀');
+  expect(input.element.value).toEqual('1😀😀😀');
+});