javascript - 如何从对象数组中提取多属性重复项？

Question

我有一个对象数组，其中属性可能共享相同的值:

const arr = [
  {name: 'Stephan', phone: 123},
  {name: 'Stephan', phone: 432},
  {name: 'Begal', phone: 432},
  {name: 'Lucy', phone: 777},
  {name: 'Angel', phone: 432},
  {name: 'Lucy', phone: 555},
  {name: 'Mike', phone: 999},
];

(您可以观察到姓名或电话可以重复多次)。

我需要在单独的数组/对象中提取具有重复电话/姓名的对象以进行进一步操作。

理想情况下，从上面的示例生成的重复数组可能如下所示:

const dups = [
  [
    {name: 'Stephan', phone: 123},
    {name: 'Stephan', phone: 432},
    {name: 'Begal', phone: 432},
    {name: 'Angel', phone: 432},
  ],
  [
    {name: 'Lucy', phone: 777},
    {name: 'Lucy', phone: 555},
  ]
];

如何实现这一目标？

我的算法知识不强，但我想按姓名和电话对原始数组进行排序将是第一步？

Answer 1

无需排序。迭代数组并维护两个辅助索引，表示“姓名/电话 X 在 Y 组中”:

const arr = [
    {name: 'Stephan', phone: 123},
    {name: 'Stephan', phone: 432},
    {name: 'Begal', phone: 432},
    {name: 'Lucy', phone: 777},
    {name: 'Angel', phone: 432},
    {name: 'Lucy', phone: 555},
    {name: 'Mike', phone: 999},
];


var groups = [[]],
    names = {},
    phones = {};

for (var obj of arr) {
    var g = names[obj.name] || phones[obj.phone];
    if (!g)
        groups[g = groups.length] = [];
    groups[g].push(obj);
    names[obj.name] = phones[obj.phone] = g;
}

console.log(groups.slice(1))