根据值列表过滤 json 数组

Question

我是 Angular 2 打字稿的新手，但我遇到了一种情况。 我有一个这种格式的 json 数组

needle json 
[{"empId":100,"orgId":500}
{"empId":201,"orgId":566}]

上面的 json 有一个特定的顺序，我们需要保持这个顺序，同时在另一个 json 数组（Haystack）中寻找它们

Haystack json array
[
{"empCode":21,"fname":"Ashish","Lname":"Shukla"},
{"empCode":22,"fname":"John","Lname":"Mark"},
{"empCode":21,"fname":"Vigil","Lname":"Rocker"},
{"empCode":201,"fname":"Rick","Lname":"Mandez"},
{"empCode":21,"fname":"Erik","Lname":"Francis"},
{"empCode":100,"fname":"Alex","Lname":"Mishra"},
{"empCode":21,"fname":"Feeder","Lname":"Kapoor"},
{"empCode":21,"fname":"Dan","Lname":"Rox"},
{"empCode":21,"fname":"Herb","Lname":"Deen"},
{"empCode":21,"fname":"Nate","Lname":"Diaz"},
{"empCode":21,"fname":"Nick","Lname":"Diaz"},
{"empCode":21,"fname":"Conor","Lname":"Pussy"}
]

现在我需要从 haystack 数组中获取那些 id 与 needle 匹配的值，保持针的顺序

{"empCode":100,"fname":"Alex","Lname":"Mishra"},
{"empCode":201,"fname":"Rick","Lname":"Mandez"}

我已经解决了这个问题，但我想我的解决方案不是最优的，因为我使用了很多循环。有人可以建议我一个好的解决方案吗？

请注意：应在结果 json 中维护员工 ID 的顺序，与针头 json 一样。

非常感谢:)

Answer 1

这应该可以工作

public needle: any;
public hayStack: any;

this.needle = [
{"empId": 100, "orgId": 500},
{"empId": 201, "orgId": 566}
];

this.hayStack = [
{"empCode":21,"fname":"Ashish","Lname":"Shukla"},
{"empCode":22,"fname":"John","Lname":"Mark"},
{"empCode":21,"fname":"Vigil","Lname":"Rocker"},
{"empCode":201,"fname":"Rick","Lname":"Mandez"},
{"empCode":21,"fname":"Erik","Lname":"Francis"},
{"empCode":100,"fname":"Alex","Lname":"Mishra"},
{"empCode":21,"fname":"Feeder","Lname":"Kapoor"},
{"empCode":21,"fname":"Dan","Lname":"Rox"},
{"empCode":21,"fname":"Herb","Lname":"Deen"},
{"empCode":21,"fname":"Nate","Lname":"Diaz"},
{"empCode":21,"fname":"Nick","Lname":"Diaz"},
{"empCode":21,"fname":"Conor","Lname":"Pussy"}
];

const needleEmpId = this.needle.map(item => item.empId);
const hayStackEmpCode = this.hayStack.map(item => item.empCode);

const result = hayStackEmpCode.map((id, index) => {
if (needleEmpId.indexOf(id) != -1) {
  return this.hayStack[index];
}
}).sort().filter(item => (item != undefined));

console.log(result);

结果

0:{empCode: 100, fname: "Alex", Lname: "Mishra"}

1:{empCode: 201, fname: "Rick", Lname: "Mandez"}