pivot-editor/index.html

<script>
var N = {
    Create:(inMeta, ...inChildren) =>
    {
        var output = {
            Meta:inMeta,

            Children:[],
            Parents:[],
            WalkID:0,

            GetUpward:[],
            GetDownward:[],
            GetOutside:[],

            SetUpward:[],
            SetDownward:[],
            SetOutside:[]
        };
        inChildren.forEach( inChild => N.Connect(output, "Children", inChild, "Parents") );
        return output;
    },
    Connect:(inParent, inParentRefs, inChild, inChildRefs) =>
    {
        inParent[inParentRefs].push(inChild);
        inChild[inChildRefs].push(inParent);
    },
    Disconnect:(inParent, inParentRefs, inChild, inChildRefs) =>
    {
        let checkRemove = (inArray, inMember) =>
        {
            inArray.findIndex( (inMember, inIndex, inArray) => (inMember === match) ? inArray.splice(inIndex, 1) : false );
        };
        checkRemove(inParent[inParentRefs], inChild);
        checkRemove(inChild[inChildRefs], inParent);
    },
    Walk:(inNode, inKey, inIterator, inWalkID) =>
    {
        let array = inNode[inKey];
        for(let i=0; i<array.length; i++)
        {
            let next = array[i];
            if(next.WalkID !== inWalkID)
            {
                next.WalkID = inWalkID;
                let results = inIterator(next);
                if(results !== false)
                {
                    N.Walk(next, inKey, inIterator, inWalkID);
                }
            }
        }
    },
    Modify(inNode)
    {
        inNode.WalkID = "tweak-"+Math.random();

        let leaves = [];
        let gatherUp = n => N.Connect(inNode, "SetUpward", n, "GetUpward");
        let gatherDown = n =>
        {
            N.Connect(inNode, "SetDownward", n, "GetDownward");
            n.Children.length == 0 ?  leaves.push(n) : null;
        };
        let gatherOut = n => N.Connect(inNode, "SetOutside", n, "GetOutside");

        N.Walk(inNode, "Parents", gatherUp, inNode.WalkID);
        N.Connect(inNode, "SetDownward", inNode, "GetDownward");
        N.Walk(inNode, "Children", gatherDown, inNode.WalkID);
        leaves.forEach(leaf=>N.Walk(leaf, "Parents", gatherOut, inNode.WalkID));
    }
};
</script>
<script>
let tree1 = N.Create("root1",
    N.Create("branch1", 
        N.Create("leaf1"),
        N.Create("leaf2"),
        N.Create("leaf3"),
    ),
    N.Create("branch2",
        N.Create("leaft3"),
        N.Create("leaft4")
    )
);

let leaves = [];
let leavesCollect = n =>
{
    if(n.Children.length == 0)
    {
        leaves.push(n);
    }
};
N.Walk(tree1, "Children", leavesCollect, 1);

let tree2 = N.Create("root2", 
    N.Create("branch3",
        N.Create("leaf5"),
        N.Create("leaf6")
    ),
    N.Create("branch4", ...leaves)
);

let orchard = N.Create("orchard", tree1, tree2);


/*************************************************************/

N.Modify(tree1);
console.log(tree1);

</script>