javascript - 如何使用 lodash 改进此例程？

我写了一些我不自豪的代码，作为一个 lodash 新手，我希望能得到一些关于如何改进这段代码的反馈。

要求是为某些类型的折扣用默认值填充时间段数组，例如：

例如，每个时间段（从左侧向下）每个折扣（顶行）都有6张桌子。在中午12点，20%折扣列中有2张桌子，等等。在右侧是每个时间段的总数。

我目前有这样的数据格式：

class DiscountTimeTable {
    public restaurantScheduleDiscountId: number;
    public scheduleDiscountId: number;
    public name: string;
    public tables: number;
}

class TablesForTimesAndDiscount {
    public restaurantScheduleDayTimeId: number;
    public timeSlot: string;
    public discounts: Array<DiscountTimeTable>;
}

然后我对时间段做一个 foreach 循环，然后对每个时间段，再做一个 foreach 循环遍历所有折扣。然后，如果折扣匹配 X，我检查该时间和折扣是否在另一个数组（discount20Times）中，如果在，则执行某些操作。

代码可以运行，但我确定它效率不高——我只是不知道应该用 Lodash 采取什么方法来改进它？

public resetDefaults(): void {
        let discount10Times: string[] = ['PT13H30M', 'PT16H30M', 'PT19H30M', 'PT22H30M'];
        let discount20Times: string[] = ['PT12H', 'PT12H30M', 'PT13H', 'PT17H', 'PT17H30M', 'PT18H', 'PT18H30M', 'PT19H', 'PT23H'];

    _.forEach(this.tablesForTimesAndDiscounts, (tablesForTimesAndDiscount: TablesForTimesAndDiscount) => {
        _.forEach(tablesForTimesAndDiscount.discounts, (discount: DiscountTimeTable) => {
            if (discount.scheduleDiscountId === 0) {
                discount.tables = 6;  //regardless of time - all tables
            }
            if (discount.scheduleDiscountId === 10) {
                if (_.find(discount10Times, (time: string) => time == tablesForTimesAndDiscount.timeSlot)) {
                    discount.tables = 2;
                }
            }
            if (discount.scheduleDiscountId === 20) {
                if (_.find(discount20Times, (time: string) => time == tablesForTimesAndDiscount.timeSlot)) {
                    discount.tables = 2;
                }
            }
        });
    });
}

答案＃1

你可以立即通过使用对象而不是数组来加快查找速度（类型声明可能不正确，但你明白意思）

我缩短了其中一个变量名，只是为了让它更容易阅读

public resetDefaults(): void {
  let discount10Times: Object<string> = {
    PT13H30M: 'PT13H30M', 
    PT16H30M: 'PT16H30M',
    PT19H30M: 'PT22H30M'
  };
  let discount20Times: Object<string> = {
    PT12H:    'PT12H', 
    PT12H30M: 'PT12H30M',
    PT13H:    'PT13H',
    PT17H:    'PT17H',
    PT17H30M: 'PT17H30M',
    PT18H:    'PT18H',
    PT18H30M: 'PT18H30M',
    PT19H:    'PT19H',
    PT23H:    'PT23H'
  };

  _.forEach(this.tablesForTimesAndDiscounts, (timesAndDiscount: TablesForTimesAndDiscount) => {
        _.forEach(timesAndDiscount.discounts, (discount: DiscountTimeTable) => {
          if (discount.scheduleDiscountId === 0) {
            discount.tables = 6;  //regardless of time - all tables
          }
          if (discount.scheduleDiscountId === 10) {
            if (discount10Times[timesAndDiscount.timeSlot]) {
              discount.tables = 2;
            }
          }
          if (discount.scheduleDiscountId === 20) {
            if (discount20Times[timesAndDiscount.timeSlot]) {
              discount.tables = 2;
            }
          }
        });
    });
}