需求：

將key為123的對象，替換成newObj，他們的key相同

知識點

for循環(huán)--更改原數(shù)組

let obj = {
  key:'111'
  title: 'title',
  children:[
     {
        key:'123'
        title: '舊title',
     }
  ]
}
let newObj = {
   key:'123'
   title: '新title'
}



let editTreeData = (treeData,newTreeNode) => { 
    for (let i = 0, len = treeData.length; i < len; i++) { 
      if(treeData[i].children){
          this.editTreeData(treeData[i].children,newTreeNode)
        }   
      if (treeData[i].key === newTreeNode.key) {
        treeData[i] = newTreeNode;
      }
    }
    return treeData 
}



editTreeData(obj,newObj)

// 輸出
let obj = {
  key:'111'
  title: 'title',
  children:[
     {
        key:'123'
        title: '新title',
     }
  ]
}