如何修复错误值不可迭代的问题

Question

在我的表中，我通过输出值来迭代各行。一旦没有值，我就会得到错误value is not iterable。我该如何解决这个错误呢？

我的代码：

if (null != data && data) {
  
data = data.map((item) => {
   const value = item.deadlineEntityList;
      delete item.deadlineEntityList;
        const deadlines = [];
            for (const deadlineEntity of value) { // Here is the Error
              deadlines.push({
                deadlineId: deadlineEntity.deadlineId,
                period: deadlineEntity.deadlinePeriod,
                value: deadlineEntity.value
              });
            }
            return {...item, ...{ deadlines }};
          });

          const rows = [];
          const salesAreaNames = _.uniq(data.map((d) => d.kagName)) as string[];
          for (const n of salesAreaNames) {
            const salesAreaData = data.find((d) => d.kagName === n);
            if (salesAreaData && salesAreaData !== null) {
              const row: any = { kagName: salesAreaData.kagName, values: {}, mandantKagId: salesAreaData.mandantKagId };
              for (const deadline of salesAreaData.deadlines) {
                row.values[deadline.period.toLowerCase()] = this.transformAmount(deadline.value);
              }
              rows.push(row);
            }
          }
          this.data = rows;
        }

Answer 1

你可以做到：

​

 for (const deadlineEntity of (value ?? [])) { // Here is the Error

​

它将防止该值出现错误，因为如果它没有某个值，它将迭代[]

Answer 2

试试这样的..。

const data = [];

if (null != data && data) {
  data = data.map((item) => {
    let { deadlineEntityList, ...itemWithoutDeadlineEntityList } = item;

    deadlineEntityList = deadlineEntityList || [];

    const deadlines = deadlineEntityList.map((deadlineEntity) => {
      return {
        deadlineId: deadlineEntity.deadlineId,
        period: deadlineEntity.deadlinePeriod,
        value: deadlineEntity.value,
      };
    });
    return { ...itemWithoutDeadlineEntityList, deadlines };
  });

  const rows = [];
  const salesAreaNames = _.uniq(data.map((d) => d.kagName)) as string[];

  salesAreaNames.forEach((salesAreaName) => {
    const salesAreaData = data.find((d) => d.kagName === salesAreaName);
    const row: any = {
      kagName: salesAreaData.kagName,
      values: {},
      mandantKagId: salesAreaData.mandantKagId,
    };

    salesAreaData.deadlines.forEach((deadline) => {
      row.values[deadline.period.toLowerCase()] = this.transformAmount(
        deadline.value,
      );
    });

    rows.push(row);
  });

  this.data = rows;
}

为了帮助阅读代码，我建议您始终格式化代码。试一试像Prettier这样的工具。