An element with non-undefined children should clear the node’s actual children.

[brainkim]

Rendering something like <div>{[]}</div> will fail to clear the div of user-created DOM nodes (my current use-case is a content-editable). This was done so that the user could manually insert children into crank-created DOM nodes without having Crank interfere. Currently, we check the length of the normalized array of child nodes passed into the arrange() method, but I sorta want DOM nodes to be cleared in the case of an empty array, or a component element with no children, for instance. Maybe we could refine the heuristic to check that the actual children prop is nullish or maybe even undefined. Think more about this heuristic.

Related to #158, except that issue concerns the root DOM node which we render into, while this issue seems more about any rendered DOM node, and in this issue we want the opposite effect (clear out the DOM node as opposed to preserve the DOM node’s previous children).

[brainkim]

My current thinking is that this behavior should be based on a "children" in el.props test, which would align with how we handle other props. In other words, if no children are defined on props, we avoid arranging the element’s children.

This would technically be a breaking change.

[brainkim]

On second thought, I think I’m gonna make this a non-breaking change because whenever I encounter this behavior it feels more like a bug than anything.

[brainkim]

On third thought, while doing an in check against the props object would technically make the children prop more like other props, that would be a more disruptive change as people might be surprised that rendering a node without children (<div />) doesn’t clear previously rendered children. I think such a change would have to be deferred to a major version change, if we actually wanted this behavior.

[brainkim]

“Fixed” or “Changed” in 0.3.7