js--数组分类

原数组：

let arr = [
        {
            id:1,
            key: "计划中",
            value: "E0001"
        },
        {
            id:2,
            key: "已完成",
            value: "E0006"
        },
        {
            id:3,
            key: "计划中",
            value: "E0007"
        },
        {
            id:4,
            key: "已取消",
            value: "E0008"
        }
    ]        

分类一：

const getNewArr = arr => {
    let newArr = [];
    arr.map(mapItem => {
      if (newArr.length == 0) {
        newArr.push({ value: mapItem.value, list: [mapItem] });
      } else {
        let res = newArr.some(item => {
          if (item.value == mapItem.value) {
            item.list.push(mapItem);
            return true;
          }
        });
        if (!res) {
          newArr.push({ value: mapItem.value, list: [mapItem] });
        }
      }
    });
    console.log(newArr);
  };

分类二：

const getNewArr = arr => {
    let list = arr,
      data = [];
    for (let i = 0; i < list.length; i++) {
      if (!data[list[i].key]) {
        let arr = [];
        arr.push(list[i]);
        data[list[i].key] = arr;
      } else {
        data[list[i].key].push(list[i]);
      }
    }
    console.log(data)
  };