从数组中获取一天中的最低和最高时间答案

【问题标题】：Fetching Lowest and Highest Time of the Day from Array从数组中获取一天中的最低和最高时间
【发布时间】：2020-02-02 11:07:31
【问题描述】：

我有一个这样的对象数组

const timings = [{
        monday: { from: "12:00", to: "13:00" },
        tuesday: { from: "11:00", to: "13:00" },
        thursday: { from: "11:00", to: "13:00" },
        friday: { from: "11:00", to: "13:00" },
        saturday: { from: "11:00", to: "13:00" },
    },

    {
        monday: { from: "10:00", to: "17:00" },
        tuesday: { from: "09:00", to: "10:00" },
        thursday: { from: "05:00", to: "13:00" },
        friday: { from: "02:00", to: "13:30" },
        saturday: { from: "11:00", to: "13:00" },
    },

    {
        monday: { from: "13:00", to: "14:20" },
        tuesday: { from: "11:00", to: "13:00" },
        thursday: { from: "11:00", to: "13:00" },
        friday: { from: "11:00", to: "13:00" },
        saturday: { from: "11:00", to: "13:00" },
    },

    {
        monday: { from: "12:00", to: "13:00" },
        tuesday: { from: "11:00", to: "13:40" },
        thursday: { from: "11:00", to: "16:00" },
        friday: { from: "11:00", to: "13:00" },
        saturday: { from: "11:00", to: "13:00" },
        sunday: {from: "00:00", to: "23:59"}
    },
]

我希望输出包含数组中一天中最低和最高的时间

例如输出：

{
    monday: { from: "10:00", to: "17:00" },
    tuesday: { from: "09:00", to: "13:40" },
    thursday: { from: "05:00", to: "16:00" },
    friday: { from: "02:00", to: "13:30" },
    saturday: { from: "11:00", to: "13:00" },
    sunday: {from: "00:00", to: "23:59"}
}

我想出了一个很长的解决方案，但它很长而且效率不高。

我的解决方案

mondayFrom = timings.map(d => (d.monday && d.monday.from))
mondayTo = timings.map(d => (d.monday && d.monday.to))
tuesdayFrom = timings.map(d => (d.tuesday && d.tuesday.to))
// .... rest of the days

这将生成数组，我可以从中找到最小值和最大值，但我觉得它的逻辑很糟糕。

如果有更好的方法，请告诉我。谢谢

【问题讨论】：

我会使用reduce
请通读help center，尤其是How do I ask a good question?，你最好的办法是做你的研究，search关于SO的相关主题，然后试一试。如果您在进行更多研究和搜索后遇到困难并且无法摆脱困境，请发布您的尝试minimal reproducible example，并具体说明您遇到困难的地方。人们会很乐意提供帮助。
我可以知道我在这里违反了什么规则吗？
好吧，这取决于这一系列时间是否会改变？多常？用户说如何改变它？你还需要对时间做点别的吗？

标签： javascript node.js momentjs

【解决方案1】：

使用 reduce 让它变得相当简单

const timings = [{
        monday: { from: "12:00", to: "13:00" },
        tuesday: { from: "11:00", to: "13:00" },
        thursday: { from: "11:00", to: "13:00" },
        friday: { from: "11:00", to: "13:00" },
        saturday: { from: "11:00", to: "13:00" },
    },

    {
        monday: { from: "10:00", to: "17:00" },
        tuesday: { from: "09:00", to: "10:00" },
        thursday: { from: "05:00", to: "13:00" },
        friday: { from: "02:00", to: "13:30" },
        saturday: { from: "11:00", to: "13:00" },
    },

    {
        monday: { from: "13:00", to: "14:20" },
        tuesday: { from: "11:00", to: "13:00" },
        thursday: { from: "11:00", to: "13:00" },
        friday: { from: "11:00", to: "13:00" },
        saturday: { from: "11:00", to: "13:00" },
    },

    {
        monday: { from: "12:00", to: "13:00" },
        tuesday: { from: "11:00", to: "13:40" },
        thursday: { from: "11:00", to: "16:00" },
        friday: { from: "11:00", to: "13:00" },
        saturday: { from: "11:00", to: "13:00" },
        sunday: {from: "00:00", to: "23:59"}
    },
]

let result = timings.reduce((a, x) => {
    Object.entries(x).forEach(([dow, obj]) => {
        if(!a[dow]) {
            a[dow] = Object.assign({}, obj);
        } else {
            a[dow].from = a[dow].from < obj.from ? a[dow].from : obj.from;
            a[dow].to = a[dow].to > obj.to ? a[dow].to : obj.to;
        }
    });
    return a;
}, {});

console.log(result);

注意：a[dow] = Object.assign({}, obj); 所以原始对象不会发生变异

【讨论】：

【解决方案2】：

这里是一个使用.reduce的例子：

const timings = [{
        monday: { from: "12:00", to: "13:00" },
        tuesday: { from: "11:00", to: "13:00" },
        thursday: { from: "11:00", to: "13:00" },
        friday: { from: "11:00", to: "13:00" },
        saturday: { from: "11:00", to: "13:00" },
    },

    {
        monday: { from: "10:00", to: "17:00" },
        tuesday: { from: "09:00", to: "10:00" },
        thursday: { from: "05:00", to: "13:00" },
        friday: { from: "02:00", to: "13:30" },
        saturday: { from: "11:00", to: "13:00" },
    },

    {
        monday: { from: "13:00", to: "14:20" },
        tuesday: { from: "11:00", to: "13:00" },
        thursday: { from: "11:00", to: "13:00" },
        friday: { from: "11:00", to: "13:00" },
        saturday: { from: "11:00", to: "13:00" },
    },

    {
        monday: { from: "12:00", to: "13:00" },
        tuesday: { from: "11:00", to: "13:40" },
        thursday: { from: "11:00", to: "16:00" },
        friday: { from: "11:00", to: "13:00" },
        saturday: { from: "11:00", to: "13:00" },
        sunday: {from: "00:00", to: "23:59"}
    },
];

const formatTimings = function(timings) {

  return timings.reduce(function(result, timing) {
    Object.keys(timing).forEach(function(key) {
      result[key] = {
        from: !result[key] 
          ? timing[key].from 
          : [result[key].from, timing[key].from].sort()[0],
        to: !result[key]
          ? timing[key].to
          : [result[key].to, timing[key].to].sort().reverse()[0]
      };
    })
    return result
  }, {})

}

console.log(formatTimings(timings));

【讨论】：