Arest's questions

const tree = [
    {
        v: 5,
        c: [
            {
                v:10,
                c: [
                    {
                        v:11,
                    }
                ]
            },
            {
                v:7,
                c: [
                    {
                        v:5,
                        c: [
                            {
                                v:1
                            }
                        ]
                    }
                ]
            }
        ]
    },
    {
        v: 5,
        c: [
            {
                v:10
            },
            {
                v:15
            }
        ]
    }
]

function treeSum(tree) {
    let sum = 0;
    
    for (let i = 0; i < tree.length; i++) {
        sum+= tree[i].v;
        if (!tree[i].c) {
            return tree[i].v;
        }
         sum += treeSum(tree[i].c)
        
    }
 /*    tree.forEach((node,index)=>{
         index;
        sum += node.v
        if (!node.c) {
            return node.v;
        }
         sum += treeSum(node.c)
        
    }) */
 /* c foreach все работает*/
  return sum
}