javascript - 如何从复杂对象数组中获取唯一属性数组

Question

我有一个类似于

的对象数组

const array = [
{
    documentId: "document1",
    writers: [
        {
            name: "writer1", 
            date: "2017-12-11"
        },
        {
            name: "writer2", 
            date: "2017-12-11"
        }
    ]
},
{
    documentId: "document2",
    writers: [
        {
            name: "writer1", 
            date: "2017-12-11"
        },
        {
            name: "writer3", 
            date: "2017-12-11"
        }
    ]
},
{
    documentId: "document3",
    writers: [
        {
            name: "writer3", 
            date: "2017-12-11"
        },
        {
            name: "writer4", 
            date: "2017-12-11"
        }
    ]
},

我正在尝试提取所有唯一作者的姓名并将它们与他们编写的所有文档进行匹配，以便最终数组看起来像这样:

const finalArray = [
    {name: "writter1", documents: ["document1", "document2"]},
    {name: "writter2", documents: ["document1"]},
    {name: "writter3", documents: ["document2", "document3"]},
    {name: "writter4", documents: ["document3"]}
]

Answer 1

您可以使用 Map 将 writers 作为键，然后调用数组上的 reduce 将文档映射到 writer，然后调用 values()在 Map 对象上:

const ret = Array.from(array.reduce((acc, val) => {
  val.writers.forEach(({ name }) => {
    let w = acc.get(name) || { name: name, documents: [] };
    w.documents = w.documents.concat(val.documentId);
    acc.set(name, w);
  });
  return acc;
}, new Map()).values());

console.log(ret);