hamt.js
function IndexedNode(edit, mask, children) {
    return {
        type: INDEX,
        edit: edit,
        mask: mask,
        children: children,
        _modify: IndexedNode__modify
    };
}
function IndexedNode(edit, mask, children) {
    return {
        type: INDEX,
        edit: edit,
        mask: mask,
        children: children,
        _modify: IndexedNode__modify
    };
}
function IndexedNode ( edit , mask , children ) { return { type : INDEX , edit : edit , mask : mask , children : children , _modify : IndexedNode__modify } ; }
Internal node with a sparse set of children.

Uses a bitmap and array to pack children.

@member edit Edit of the node.
@member mask Bitmap that encode the positions of children in the array.
@member children Array of child nodes.
Internal node with a sparse set of children .