如何對數組對象 json javascript 進行分組（Angular 5）

Question

我正在嘗試幾種方法來對一組對象 json 進行分組，但我不能這樣做，這是初始數組：

{_id: "455", name: "ALBACETE"}
{_id: "455", name: "ALLICANTE"}
{zone: {_id: "zone1", name: "zone1"}, _id: "143", name: "ALCALA"}
{zone: {_id: "zone1", name: "zone1"}, _id: "144", name: "OTRO"}
{zone: {_id: "zone2", name: "zone2"}, _id: "144", name: "OTRO MAS"}

也就是說，數組中有些元素沒有區域，而其他元素則是。

我希望得到這樣的結果：

{_id: "455", name: "ALBACETE"}
{_id: "455", name: "ALLICANTE"}
{zone: {_id: "zone1", name: "zone1"}, _id: "144", name: "OTRO"}
{zone: {_id: "zone2", name: "zone2"}, _id: "144", name: "OTRO MAS"}

即按zone分組（zone1不重復）。

我試試這個：

const q = [
     { zone: { _id: "zone1", name: "zone1" }, _id: "143", name: "ALCALA" },
     { zone: { _id: "zone1", name: "zone1" }, _id: "144", name: "OTRO" },
     { zone: { _id: "zone2", name: "zone2" }, _id: "144", name: "OTRO MAS" },
     { _id: "455", name: "ALBACETE" }
     {_id: "455", name: "ALLICANTE"}
 ];``


let ret = [];

let result = q.filter( x => {
  if(!ret.includes(x._id)) {
    ret.push(x._id);
    return true;
  }
  return false;
});

But the output does not filter by the object "zone":

[ 
   { zone: { _id: 'zone1', name: 'zone1' }, _id: '143', name: 'ALCALA' },
   { zone: { _id: 'zone1', name: 'zone1' }, _id: '144', name: 'OTRO' },
   { _id: '455', name: 'ALBACETE' } 

Answer 1

好的，我已經設法以這種方式解決了這個問題：一個forEach遍歷數組和JSON.stringify()來比較值。