When setting boolean attributes on Web Components
`<x-search somebool name={this.props.name} />`
they get rendered as attribute/value pairs instead
`<x-search somebool="true" name={this.props.name}>`

This causes problems with some AMP components, for eg. `<amp-iframe />` which has a `resizable` attribute that gets rendered as `resizable="true"`. This results in non valid AMP content and developers crying with blood tears on their keyboards :)
> The attribute 'resizable' in tag 'amp-iframe' is set to the invalid value 'true'. (see https://www.ampproject.org/docs/reference/components/amp-iframe)

Is there any reason for the current behaviour? Will changing this break something else?
el = ReactTestUtils.renderIntoDocument(<div hidden="false" />);
      }).toErrorDev(
        'Received the string `false` for the boolean attribute `hidden`. ' +
          'The browser will interpret it as a truthy value. ' +
          'Did you mean hidden={false}?',
      );
      expect(el.getAttribute('hidden')).toBe('');
    });
    it('warns on the potentially-ambiguous string value "true"', function() {
      let el;
      expect(() => {
        el = ReactTestUtils.renderIntoDocument(<div hidden="true" />);
      }).toErrorDev(
        'Received the string `true` for the boolean attribute `hidden`. ' +
          'Although this works, it will not work as expected if you pass the string "false". ' +
          'Did you mean hidden={true}?',
      );
      expect(el.getAttribute('hidden')).toBe('');
    });
  });
  describe('Hyphenated SVG elements', function() {
    it('the font-face element is not a custom element', function() {
      let el;
      expect(() => {
        el = ReactTestUtils.renderIntoDocument(
          <svg>
            <font-face x-height={false} />
          </svg>,
        );
      }).toErrorDev(