[JS] O(n) easy to understand
\nvar mergeNodes = function(head) {\n    let count = 0;\n    \n    let node = head; // start on first zero\n    \n    while(node.next) {\n        node.val += no
```\nvar mergeNodes = function(head) {\n    let count = 0;\n    \n    let node = head; // start on first zero\n    \n    while(node.next) {\n        node.val += node.next.val; // add current value to node\n        node.next = node.next.next; // remove value between zeroes\n        \n        // remove last zero\n        if(!node.next.next) {\n            node.next = null;\n            break;\n        }\n        // traverse node to next 0\n        if(node.next.val === 0) {\n            node = node.next;\n        }\n    }\n    \n    return head;\n};```
['JavaScript']