javascript - 使用 spread 减少 es6 丢失的嵌套对象数组

Question

我在按条件合并 2 组数据时遇到问题。我已经调试了一个多小时，但无法弄清楚为什么。我在下面创建了一个示例。

我有这两个数据:

const staticRockData = {
    rockTypes: [
      {
        supplierRockTypes: [
          {
            rockCodes: ["1"],
            match_id: "abc"
          },
          {
            rockCodes: ["2"],
            match_id: "abc"
          }
        ]
      }
    ]
  };

  const gatewayRockData = {
    match_id: "abc",
    rocks: [{ rock_type: "1", rates: [] }, { rock_type: "2", rates: [] }]
  };

我有这个映射逻辑:

let rockTypes = staticRockData.rockTypes;

  rockTypes = rockTypes.reduce((accum, rockType) => {
    const matchedSourceId = rockType.supplierRockTypes.some(
      o2 => o2.match_id === gatewayRockData.match_id
    );
    if (matchedSourceId) {
      gatewayRockData.rocks.forEach(rock => {
        const matchRockType = rockType.supplierRockTypes.some(o2 => {
          return o2.rockCodes.includes(rock.rock_type);
        });

        if (matchRockType) {
          console.log("rock.rock_type", rock.rock_type);
          rockType = {
            ...rockType,
            rock_type: rock.rock_type,
            rates: rock.rates
          };
        }
      });
    }

    accum = [...accum, { ...omit(rockType, "supplierRockTypes") }];

    return accum;
  }, []);

  return {
    rocks: rockTypes
  };

我期望这样:

rocks: [
       {
         rates: [],
         rock_type: "1"
       },
       {
         rates: [],
         rock_type: "2"
       }
     ]
   }

当前的解决方案缺少这个:

{ rates: [], rock_type: "1"}，我想知道我的错误在哪里。

Omit 是 lodash 的 omit 函数，但我不认为这是罪魁祸首。我在这里创建了一个演示:

https://codesandbox.io/s/condescending-platform-1jp9l?fontsize=14&previewwindow=tests

Answer 1

每次重复循环都会覆盖 rockType:

rockType = {
        ...rockType,
        rock_type: rock.rock_type,
        rates: rock.rates
      };

您应该以这种方式将结果存储在另一个变量中:

...
let matchedRockTypes = [];
if (matchedSourceId) {
  gatewayRockData.rocks.forEach(rock => {
    const matchRockType = rockType.supplierRockTypes.some(o2 => {
      return o2.rockCodes.includes(rock.rock_type);
    });

    if (matchRockType) {
      console.log("rock.rock_type", rock.rock_type);
      matchedRockTypes.push({
        rock_type: rock.rock_type,
        rates: rock.rates
      });
    }
  });
}
return matchedRockTypes;
...

结果如下: https://codesandbox.io/s/tender-ritchie-i0qkt