Object tree traversal in vanilla javascript

forEachTreeNode.js

// Usage example: 
forEachTreeNode(tree, (node) => {
  console.log(node.title);
});


// Implementation
const forEachTreeNode = (obj, func): void => {
  if (!obj) return;
  func(obj);
  if (obj.children && obj.children.length > 0) {
    obj.children.forEach((x) => forEachTreeNode(x, func));
  }
};

// Acceptable Tree structure: 
 const tree = { title: 'Main node!', children: [
  { title: 'node 1' },
  { title: 'node 2', children: [
    { title: 'node 2.1' },
    { title: 'node 2.2', children: [
      { title: 'node 2.2.1' },
      { title: 'node 2.2.2' },
      { title: 'node 2.2.3' },
    ] },
    { title: 'node 2.3' },
  ] },
  { title: 'node 3' },
]};

// Output of "forEachTreeNode(tree, (node) => console.log(node.title));"
// Main node!
// node 1
// node 2
// node 2.1
// node 2.2
// node 2.2.1
// node 2.2.2
// node 2.2.3
// node 2.3
// node 3