DropdownMenu setActiveFromChild cannot handle null as child

[Psvensso]

• components: Dropdown
• reactstrap version #6.5.0
• import method cjs
• react version #16.5.1

What is happening?

A very common pattern is the && checks for JSX syntax.
When using this yntax the JSX element can be "null". This unfortunately also requires the component to check for null´s when iterating through the children.

Note:
This is only true for when using the setActiveFromChild prop.

What should be happening?

It should not throw an error complaining about "null"

Steps to reproduce issue

From example but with a dummy && check.

<UncontrolledDropdown setActiveFromChild>
          <DropdownToggle tag="a" className="nav-link" caret>
            Dropdown
          </DropdownToggle>
          <DropdownMenu>
            <DropdownItem tag="a" href="/blah" active>Link</DropdownItem>
            { null && <DropdownItem tag="a" href="/blah" active>Link</DropdownItem> }
          </DropdownMenu>
</UncontrolledDropdown>

Error message in console

Uncaught TypeError: Cannot read property 'props' of null
    at reactstrap.es.js:944
    at mapSingleChildIntoContext (react.development.js:880)
    at traverseAllChildrenImpl (react.development.js:753)
    at traverseAllChildrenImpl (react.development.js:769)
    at traverseAllChildren (react.development.js:824)
    at mapIntoWithKeyPrefixInternal (react.development.js:900)
    at Object.mapChildren [as map] (react.development.js:922)
    at ProxyComponent.render (reactstrap.es.js:943)
    at ProxyComponent.hotComponentRender (react-hot-loader.development.js:620)
    at ProxyComponent.proxiedRender (react-hot-loader.development.js:635)

Code

React.Children.map(this.props.children[1].props.children, function (dropdownItem) {
            if (dropdownItem.props.active) subItemIsActive = true;
});