根据属性的值将对象数组动态拆分为组[重复]

Question

我正在尝试动态地根据属性值将对象数组拆分为组。

这是一个输入示例：

`input = [
    {"name": "john", "location": "first"},
    {"name": "steve", "location": "first"},
    {"name": "paul", "location": "another"},
    {"name": "tony", "location": "random"},
    {"name": "ant", "location": "random"}
]`

以及所需的输出：

`solution(input, location) = [
    first:   [{"name": "john", "location": "first"},
              {"name": "steve", "location": "first"}],
    another: [{"name": "paul", "location": "another"}],
    random:  [{"name": "tony", "location": "random"},
              {"name": "ant", "location": "random"}]
]`

我不知道 location 可以是什么值（但我知道键名）

我试图避免使用任何外部库， （这是在一个 Angular 5 项目中） 但如果它使事情变得更容易，那么我并不反对。

提前致谢

Answer 1

为此使用Array#reduce：

const input = [{"name":"john","location":"first"},{"name":"steve","location":"first"},{"name":"paul","location":"another"},{"name":"tony","location":"random"},{"name":"ant","location":"random"}];

const group = input.reduce((acc, item) => {
  if (!acc[item.location]) {
    acc[item.location] = [];
  }

  acc[item.location].push(item);
  return acc;
}, {})

console.log(group);

---

编辑 1

如果你想对结果进行迭代，你可以像这样使用for...of 循环和Object.entries：

for (let [location, persons] of Object.entries(group)) {
  console.log(location, persons);
  // do your stuff here
}