背景：在前後端開發過程中，後端負責提供介面資料，有時前端需要把介面資料轉成其他的格式，本文就用於將具備父子邏輯的行資料轉成樹形結構。

程式碼如下：

function rowDataToTreeData(rootTreeNode, rowData) {
  if (rowData && rowData.length > 0) {
    for (let i = 0; i < rowData.length; i++) {
      //找出子節點
      if (rootTreeNode.id === rowData[i].parentId) {
        if (rootTreeNode.children) {
          rootTreeNode.children.push(rowData.splice(i, 1)[0]);
        } else {
          rootTreeNode.children = [rowData.splice(i, 1)[0]];
        }
        i = i - 1;
      }
    }

    if (rootTreeNode.children && rootTreeNode.children.length > 0) {
      for (let i = 0; i < rootTreeNode.children.length; i++) {
        this.rowDataToTreeData(rootTreeNode.children[i], rowData);//遞迴
      }
    }
  }

  return rootTreeNode;
}

let rootTreeNode = {//假設的根節點，便於遞迴邏輯
  id: 0,
  parentId: undefined,
  children: []
};

let rowData = [
  {
    id: 1,
    parentId: 0,
    name: 1
  },
  {
    id: 2,
    parentId: 0,
    name: 2
  },
  {
    id: 3,
    parentId: 1,
    name: 3
  },
  {
    id: 4,
    parentId: 2,
    name: 49
  },
  {
    id: 5,
    parentId: 3,
    name: 5
  },
  {
    id: 6,
    parentId: 0,
    name: 6
  },
  {
    id: 7,
    parentId: 6,
    name: 7
  },
  {
    id: 8,
    parentId: 0,
    name: 8
  },
  {
    id: 9,
    parentId: 4,
    name: 9
  },
  {
    id: 10,
    parentId: 7,
    name: 10
  },
  {
    id: 11,
    parentId: 10,
    name: 11
  },
  {
    id: 12,
    parentId: 10,
    name: 12
  }
];

console.log(rowDataToTreeData(rootTreeNode,rowData));
 

備註：資料量很大的情況並沒有測試，效能不能保證，如有道友參考需謹慎…