element is the following data format, but all the data returned in the background are nested at the object format level. How do you loop in this?

export default {

data() {
  return {
    data: [{
      label: " 1",
      children: [{
        label: " 1-1",
        children: [{
          label: " 1-1-1"
        }]
      }]
    }, {
      label: " 2",
      children: [{
        label: " 2-1",
        children: [{
          label: " 2-1-1"
        }]
      }, {
        label: " 2-2",
        children: [{
          label: " 2-2-1"
        }]
      }]
    }, {
      label: " 3",
      children: [{
        label: " 3-1",
        children: [{
          label: " 3-1-1"
        }]
      }, {
        label: " 3-2",
        children: [{
          label: " 3-2-1"
        }]
      }]
    }],
    defaultProps: {
      children: "children",
      label: "label"
    }
  };
 }
};