javascript - 对象数组，按对象键 :value 分组

Question

我有一个这样的对象数组:

const data = [
      { id: 1, type: { name: "A" }, condition: "new" },
      { id: 2, type: { name: "C" }, condition: "broken" },
      { id: 3, type: { name: "C" }, condition: "brand new" },
      { id: 4, type: { name: "B" }, condition: "broken" },
      { id: 5, type: { name: "C" }, condition: "brand new" },
      { id: 6, type: { name: "A" }, condition: "new" },
      { id: 7, type: { name: "A" }, condition: "new" },
      { id: 8, type: { name: "B" }, condition: "broken" },
      { id: 9, type: { name: "C" }, condition: "broken" }
    ];

我想做的是按类型的 key:value 对这些对象进行分组，在本例中为 name:value，如下所示:

const data = [
      {
        by: {
          type: { name: "A" }
        },
        chunks: [
          { id: 1, type: { name: "A" }, condition: "new" },
          { id: 6, type: { name: "A" }, condition: "new" },
          { id: 7, type: { name: "A" }, condition: "new" }
        ]
      },
      {
        by: {
          type: { name: "C" }
        },
        chunks: [
          { id: 2, type: { name: "C" }, condition: "broken" },
          { id: 3, type: { name: "C" }, condition: "brand new" },
          { id: 5, type: { name: "C" }, condition: "brand new" },
          { id: 9, type: { name: "C" }, condition: "broken" }
        ]
      },
      {
        by: {
          type: { name: "B" }
        },
        chunks: [
          { id: 4, type: { name: "B" }, condition: "broken" },
          { id: 8, type: { name: "B" }, condition: "broken" }
        ]
      },
    ];

我尝试使用 lodash 和 Array.prototype.reduce() ，我最后一次尝试使用 lodash，但我无法将类型作为对象。

_.chain(channels)
      .groupBy("type.name")
      .map((item, i) => {
        return {
          chunks: item,
          by: i
        };
      })
      .value();

Answer 1

您可以使用 Map 按组收集数据，然后其 values() 方法将根据需要迭代数据:

const data = [{ id: 1, type: { name: "A" }, condition: "new" },{ id: 2, type: { name: "C" }, condition: "broken" },{ id: 3, type: { name: "C" }, condition: "brand new" },{ id: 4, type: { name: "B" }, condition: "broken" },{ id: 5, type: { name: "C" }, condition: "brand new" },{ id: 6, type: { name: "A" }, condition: "new" },{ id: 7, type: { name: "A" }, condition: "new" },{ id: 8, type: { name: "B" }, condition: "broken" },{ id: 9, type: { name: "C" }, condition: "broken" }];

const map = new Map(data.map(o => [o.type.name, { by: { type: o.type.name }, chunks: [] }]));
data.forEach(o => map.get(o.type.name).chunks.push(o));
const result = [...map.values()];

console.log(result);