javascript - 从 JSON 设置父子关系

Question

我有以下 JSON 数据:

[
 {id: 1, indent: '1'},
 {id: 2, indent: '1.1'},
 {id: 3, indent: '1.2'},
 {id: 4, indent: '2'},
 {id: 5, indent: '2.1'},
 {id: 6, indent: '2.2'},
 {id: 7, indent: '2.2.1'},
 {id: 8, indent: '1.2.1'},
 {id: 9, indent: '3'},
]

我想将其转换为如下所示:

[
 {id: 1, indent: '1', parent: null},
 {id: 2, indent: '1.1', parent: 1},
 {id: 3, indent: '1.2', parent: 1},
 {id: 4, indent: '2', parent: null},
 {id: 5, indent: '2.1', parent: 4},
 {id: 6, indent: '2.2', parent: 4},
 {id: 7, indent: '2.2.1', parent: 6},
 {id: 8, indent: '1.2.1', parent: 3},
 {id: 9, indent: '3', parent: null},
]

我可以通过 2 个 for 循环(外部和内部)来实现此目的，但我正在寻找一些有效的方法来做到这一点。

ex: 
forloop each node
   get indent and check if dots ('.') are more than one
     if true
     for-loop the array and check for indent that start with the indent and ends with dot + 1

Answer 1

除非你的 json 中有超过 100000 个这样的项目(这似乎不太可能，因为下载/发送需要很长时间)，那么你的方法就可以正常工作。

您可以做的最佳优化是利用 id 有序的事实。由于引用不是，这将要求您在前进时跟踪 id 以缩进对象中的引用。

看起来像这样

var jsonObj = [
 {id: 1, indent: '1'},
 {id: 2, indent: '1.1'},
 {id: 3, indent: '1.2'},
 {id: 4, indent: '2'},
 {id: 5, indent: '2.1'},
 {id: 6, indent: '2.2'},
 {id: 7, indent: '2.2.1'},
 {id: 8, indent: '1.2.1'},
 {id: 9, indent: '3'},
];
 
var parentIds = {};  
for(var i = 0; i < jsonObj.length; i++){
 var obj = jsonObj[i];
 var dot = obj.indent.lastIndexOf('.');
 if(dot > -1){
  obj.parent = parentIds[obj.indent.substr(0,dot)];  
 }else{
  obj.parent = null;
 }
 parentIds[obj.indent] = obj.id;
}

console.log(jsonObj);
document.querySelector("#d").innerHTML = JSON.stringify(jsonObj);

<div id="d"></div>