哈希表实现id,pid转树形结构

 var source = [{
      id: 1, pid: 0, name: 'body'}, {
      id: 2, pid: 1, name: 'title'}, {
      id: 3, pid: 1, name: 'div'}, {
      id: 4, pid: 3, name: 'span'}, {
      id: 5, pid: 3, name: 'icon'}, {
      id: 6, pid: 4, name: 'subspan'}]
    function toTree(data) {
      let result = []
      if (!Array.isArray(data)) {
        return result
      }
      data.forEach(item => {
          delete item.children;
      });
      let map = {};
      data.forEach(item => {
          map[item.id] = item;
      });
      data.forEach(item => {
        let parent = map[item.pid];
        if (parent) {
            (parent.children || (parent.children = [])).push(item);
        } else {
            result.push(item);
        }
      });
      return result;
    }
    console.log(toTree(source))