JavaScript将树转换为嵌套数组

function treeToArray(tree) {
  if (!tree) {
    return [];
  }

  var result = [];

  function traverse(node, level) {
    result[level] = result[level] || [];
    result[level].push(node.value);

    if (node.children && node.children.length > 0) {
      for (var i = 0; i < node.children.length; i++) {
        traverse(node.children[i], level + 1);
      }
    }
  }

  traverse(tree, 0);

  return result;
}

// 示例树形结构
var tree = {
  value: 'A',
  children: [
    {
      value: 'B',
      children: [
        {
          value: 'D',
          children: [
            {
              value: 'G',
              children: []
            },
            {
              value: 'H',
              children: []
            }
          ]
        }
      ]
    },
    {
      value: 'C',
      children: [
        {
          value: 'E',
          children: []
        },
        {
          value: 'F',
          children: [
            {
              value: 'I',
              children: []
            },
            {
              value: 'J',
              children: []
            }
          ]
        }
      ]
    }
  ]
};

console.log(treeToArray(tree));

[
  ['A'],
  ['B', 'C'],
  ['D', 'E', 'F'],
  ['G', 'H', 'I', 'J']
]