```
render () {
  <input type="number" value={this.props.value} />
}
```

for example, when the original value is '.98', we need format it to '0.98'. but it is not  take effect。

```javascript
class Test extends React.Component {
 state = {
    value: '.98',
  }
 changeValue = () => {
    alert(0.98);
    this.setState({
      value: '0.98',
    });
  }

 render() {
    return <div>
      <input type="number" value={this.state.value} />
      <button onClick={this.changeValue}>changeValue</button>
    </div>;
  }
}

ReactDOM.render(<Test />, mountNode);
```



document.body.appendChild(container);
    
    setUntrackedValue(instance.a, 'giraffe');
    instance.a.dispatchEvent(inputEvent);
    
    expect(instance.a.value).toBe('lion');
    expect(instance.b.checked).toBe(true);
    document.body.removeChild(container);
  });
  describe('switching text inputs between numeric and string numbers', () => {
    it('does change the number 2 to "2.0" with no change handler', () => {
      var stub = <input type="text" value={2} onChange={jest.fn()} />;
      stub = ReactTestUtils.renderIntoDocument(stub);
      var node = ReactDOM.findDOMNode(stub);
      node.value = '2.0';
      ReactTestUtils.Simulate.change(stub);
      expect(node.getAttribute('value')).toBe('2');
      expect(node.value).toBe('2');
    });
    it('does change the string "2" to "2.0" with no change handler', () => {
      var stub = <input type="text" value={'2'} onChange={jest.fn()} />;
      stub = ReactTestUtils.renderIntoDocument(stub);
      var node = ReactDOM.findDOMNode(stub);
      node.value = '2.0';
      ReactTestUtils.Simulate.change(stub);
      expect(node.getAttribute('value')).toBe('2');
      expect(node.value).toBe('2');
    });
    it('changes the number 2 to "2.0" using a change handler', () => {
      class Stub extends React.Component {