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**Do you want to request a *feature* or report a *bug*?**

Bug? Mild DX improvement.

**What is the current behavior?**

Creating an input with an undefined or null value, then later passing a string value, triggers a warning about controlled inputs.

> A component is changing an uncontrolled input of type undefined to be controlled. Input elements should not switch from uncontrolled to controlled (or vice versa)

It's my experience in Reactiflux that this warning is unclear to developers with less familiarity with React, or at least with the "controlled" and "uncontrolled" terms.

expect(node.defaultValue).toBe('2000-01-01');
    }
    ReactDOM.render(<input type="date" />, container);
  });
  it('should take `defaultValue` when changing to uncontrolled input', () => {
    const node = ReactDOM.render(
      <input type="text" value="0" readOnly={true} />,
      container,
    );
    expect(node.value).toBe('0');
    expect(() =>
      ReactDOM.render(<input type="text" defaultValue="1" />, container),
    ).toErrorDev(
      'A component is changing a controlled input of type ' +
        'text to be uncontrolled.',
    );
    expect(node.value).toBe('0');
  });
  it('should render defaultValue for SSR', () => {
    const markup = ReactDOMServer.renderToString(
      <input type="text" defaultValue="1" />,
    );
    const div = document.createElement('div');
    div.innerHTML = markup;
    expect(div.firstChild.getAttribute('value')).toBe('1');
    expect(div.firstChild.getAttribute('defaultValue')).toBe(null);
  });
  it('should render value for SSR', () => {
    const element = <input type="text" value="1" onChange={() => {}} />;
    const markup = ReactDOMServer.renderToString(element);