diff --git a/package.json b/package.json
index 2531d34..6d6b02b 100644
--- a/package.json
+++ b/package.json
@@ -44,6 +44,7 @@
     "@types/react-dom": "^16.0.11",
     "@types/warning": "^3.0.0",
     "@umijs/fabric": "^1.1.9",
+    "enzyme": "^3.11.0",
     "enzyme-to-json": "^3.1.4",
     "father": "^2.13.6",
     "lodash.debounce": "^4.0.8",
diff --git a/src/Mentions.tsx b/src/Mentions.tsx
index fd36f42..9123ec6 100644
--- a/src/Mentions.tsx
+++ b/src/Mentions.tsx
@@ -72,11 +72,14 @@ class Mentions extends React.Component<MentionsProps, MentionsState> {
     rows: 1,
   };
 
-  public static getDerivedStateFromProps(props: MentionsProps, prevState: MentionsState) {
+  public static getDerivedStateFromProps(
+    props: MentionsProps,
+    prevState: MentionsState,
+  ) {
     const newState: Partial<MentionsState> = {};
 
     if ('value' in props && props.value !== prevState.value) {
-      newState.value = props.value;
+      newState.value = props.value || '';
     }
 
     return newState;
@@ -115,7 +118,9 @@ class Mentions extends React.Component<MentionsProps, MentionsState> {
     }
   };
 
-  public onChange: React.ChangeEventHandler<HTMLTextAreaElement> = ({ target: { value } }) => {
+  public onChange: React.ChangeEventHandler<HTMLTextAreaElement> = ({
+    target: { value },
+  }) => {
     this.triggerChange(value);
   };
 
@@ -166,18 +171,23 @@ class Mentions extends React.Component<MentionsProps, MentionsState> {
     const { prefix = '', onSearch, validateSearch } = this.props;
     const target = event.target as HTMLTextAreaElement;
     const selectionStartText = getBeforeSelectionText(target);
-    const { location: measureIndex, prefix: measurePrefix } = getLastMeasureIndex(
-      selectionStartText,
-      prefix,
-    );
+    const {
+      location: measureIndex,
+      prefix: measurePrefix,
+    } = getLastMeasureIndex(selectionStartText, prefix);
 
     // Skip if match the white key list
-    if ([KeyCode.ESC, KeyCode.UP, KeyCode.DOWN, KeyCode.ENTER].indexOf(which) !== -1) {
+    if (
+      [KeyCode.ESC, KeyCode.UP, KeyCode.DOWN, KeyCode.ENTER].indexOf(which) !==
+      -1
+    ) {
       return;
     }
 
     if (measureIndex !== -1) {
-      const measureText = selectionStartText.slice(measureIndex + measurePrefix.length);
+      const measureText = selectionStartText.slice(
+        measureIndex + measurePrefix.length,
+      );
       const validateMeasure: boolean = validateSearch(measureText, this.props);
       const matchOption = !!this.getOptions(measureText).length;
 
@@ -295,7 +305,11 @@ class Mentions extends React.Component<MentionsProps, MentionsState> {
     return list;
   };
 
-  public startMeasure(measureText: string, measurePrefix: string, measureLocation: number) {
+  public startMeasure(
+    measureText: string,
+    measurePrefix: string,
+    measureLocation: number,
+  ) {
     this.setState({
       measuring: true,
       measureText,
@@ -325,7 +339,13 @@ class Mentions extends React.Component<MentionsProps, MentionsState> {
   }
 
   public render() {
-    const { value, measureLocation, measurePrefix, measuring, activeIndex } = this.state;
+    const {
+      value,
+      measureLocation,
+      measurePrefix,
+      measuring,
+      activeIndex,
+    } = this.state;
     const {
       prefixCls,
       placement,
diff --git a/tests/Mentions.spec.jsx b/tests/Mentions.spec.jsx
index e31067c..d66cf80 100644
--- a/tests/Mentions.spec.jsx
+++ b/tests/Mentions.spec.jsx
@@ -32,7 +32,11 @@ describe('Mentions', () => {
 
     it('not lose focus if click on dropdown', () => {
       const onBlur = jest.fn();
-      const wrapper = createMentions({ autoFocus: true, defaultValue: '@', onBlur });
+      const wrapper = createMentions({
+        autoFocus: true,
+        defaultValue: '@',
+        onBlur,
+      });
 
       // Inject to trigger measure
       wrapper.instance().startMeasure('b', '@', 1);
@@ -45,14 +49,14 @@ describe('Mentions', () => {
       wrapper.find('textarea').simulate('focus'); // This is not good but code focus not work in simulate
       jest.runAllTimers();
 
-      expect(onBlur).not.toBeCalled();
+      expect(onBlur).not.toHaveBeenCalled();
     });
 
     it('focus', () => {
       const onFocus = jest.fn();
       const wrapper = createMentions({ onFocus });
       wrapper.find('textarea').simulate('focus');
-      expect(onFocus).toBeCalled();
+      expect(onFocus).toHaveBeenCalled();
     });
 
     it('blur', () => {
@@ -60,7 +64,7 @@ describe('Mentions', () => {
       const wrapper = createMentions({ onBlur });
       wrapper.find('textarea').simulate('blur');
       jest.runAllTimers();
-      expect(onBlur).toBeCalled();
+      expect(onBlur).toHaveBeenCalled();
     });
 
     it('focus() & blur()', () => {
@@ -69,7 +73,9 @@ describe('Mentions', () => {
       expect(document.activeElement).toBe(wrapper.find('textarea').instance());
 
       wrapper.instance().blur();
-      expect(document.activeElement).not.toBe(wrapper.find('textarea').instance());
+      expect(document.activeElement).not.toBe(
+        wrapper.find('textarea').instance(),
+      );
     });
   });
 
@@ -85,6 +91,9 @@ describe('Mentions', () => {
 
       wrapper.setProps({ value: 'cat' });
       expect(wrapper.find('textarea').props().value).toBe('cat');
+
+      wrapper.setProps({ value: undefined });
+      expect(wrapper.find('textarea').props().value).toBe('');
     });
 
     it('onChange', () => {
@@ -93,7 +102,7 @@ describe('Mentions', () => {
       wrapper.find('textarea').simulate('change', {
         target: { value: 'bamboo' },
       });
-      expect(onChange).toBeCalledWith('bamboo');
+      expect(onChange).toHaveBeenCalledWith('bamboo');
     });
   });
 
@@ -105,7 +114,9 @@ describe('Mentions', () => {
     });
 
     it('function', () => {
-      const wrapper = createMentions({ filterOption: (_, { value }) => value.includes('a') });
+      const wrapper = createMentions({
+        filterOption: (_, { value }) => value.includes('a'),
+      });
       simulateInput(wrapper, '@notExist');
       expect(wrapper.find('DropdownMenu').props().options.length).toBe(2);
     });