按 ID 对对象的 Javascript 数组进行分组

Question

我想要实现的是，如果 ID 的前两位数字匹配，则将对象组合到一个数组中。因此，鉴于以下对象数组，我想转换此原始数组：

[
    {
        "id": "0100",
        "name": "name 1",
        "message": "Lorem blah blah 1"
    },
    {
        "id": "0101",
        "name": "",
        "message": "Lorem blah blah 1.1"
    },
    {
        "id": "0200",
        "name": "name 2",
        "message": "Lorem blah blah 2"
    },
    {
        "id": "0201",
        "name": "",
        "message": "Lorem blah blah 2.1"
    },
    {
        "id": "0202",
        "name": "",
        "message": "Lorem blah blah 2.2"
    },
    {
        "id": "0300",
        "name": "name 3",
        "message": "Lorem blah blah 3"
    },
    {
        "id": "0301",
        "name": "",
        "message": "Lorem blah blah 3.1"
    },
    {
        "id": "0302",
        "name": "",
        "message": "Lorem blah blah 3.2"
    },
    {
        "id": "0303",
        "name": "",
        "message": "Lorem blah blah 3.3"
    },
    {
        "id": "0304",
        "name": "",
        "message": "Lorem blah blah 3.4"
    }
]

进入这个新阵列：

[
    {
        "id": "0100",
        "name": "name 1",
        "message": [
            "Lorem blah blah 1",
            "Lorem blah blah 1.1"
        ]
    },
    {
        "id": "0200",
        "name": "name 2",
        "message": [
            "Lorem blah blah 2",
            "Lorem blah blah 2.1",
            "Lorem blah blah 2.2"
        ]
    },
    {
        "id": "0300",
        "name": "name 3",
        "message": [
            "Lorem blah blah 3",
            "Lorem blah blah 3.1",
            "Lorem blah blah 3.2",
            "Lorem blah blah 3.3",
            "Lorem blah blah 3.4"
        ]
    }
]

需要注意的关键是，如果 ID 的前两位数字相同，则将这些对象中的消息添加在一起，如 NEW ARRAY 中所见。

正如你们所看到的，@Nenad Vracar 对上述挑战给出了一个不错的答案，但是，我还有一个涉及另一个数组的问题：

`var data2 = [{"CandidateName": "Mary", "relatedId": ["0100"]},{ "CandidateName": "John", "relatedId": ["0200"]},{ "CandidateName":"Peter", "relatedId": ["0300"]},{ "CandidateName": "Paul", "relatedId": ["0300"]}];`

我想在其中拉取 'candidateName' 并将其作为数组添加到原始数组“result”中。

我在 data1.reduce 循环中尝试了 data2.forEach 循环，但它似乎挂了。

var result = data.reduce(function(r, el) {

  // THIS INNER LOOP MAKES THE BROWSER HANG!!!
  data2.forEach(function (a){
    console.log('a',a); 
  });

  var e = el.id.slice(0, 2);
  if (!o[e]) {
    o[e] = {
      id: el.id,
      name: el.name,
      message: []
    }
    r.push(o[e]);
  }
  o[e].message.push(el.message);
  return r;
}, [])

我想知道是否有更优雅、更复杂的方法不会出错？

Answer 1

您可以使用reduce()返回数组和一个对象进行分组。

var data = [{"id":"0100","name":"name 1","message":"Lorem blah blah 1"},{"id":"0101","name":"","message":"Lorem blah blah 1.1"},{"id":"0200","name":"name 2","message":"Lorem blah blah 2"},{"id":"0201","name":"","message":"Lorem blah blah 2.1"},{"id":"0202","name":"","message":"Lorem blah blah 2.2"},{"id":"0300","name":"name 3","message":"Lorem blah blah 3"},{"id":"0301","name":"","message":"Lorem blah blah 3.1"},{"id":"0302","name":"","message":"Lorem blah blah 3.2"},{"id":"0303","name":"","message":"Lorem blah blah 3.3"},{"id":"0304","name":"","message":"Lorem blah blah 3.4"}];

var o = {}
var result = data.reduce(function(r, el) {
  var e = el.id.slice(0, 2);
  if (!o[e]) {
    o[e] = {
      id: el.id,
      name: el.name,
      message: []
    }
    r.push(o[e]);
  }
  o[e].message.push(el.message);
  return r;
}, [])

console.log(result)