Javascript从数组中获取第一个值，然后跳过它

Question

嘿，这是我到目前为止拥有的所有数组：

var thisDayDate = today.getDate();
var JANDays = [{day:16, timeStart:"23:00:00", timeEnd:"23:59:59"},  //It's Jan 16th Friday 11pm to
               {day:17, timeStart:"00:00:00", timeEnd:"11:00:00"},  //It's Jan 17th                Sat 11am
               {day:22, timeStart:"23:00:00", timeEnd:"23:59:59"},  //It's Jan 22nd Friday 11pm to  
               {day:23, timeStart:"00:00:00", timeEnd:"07:00:00"}]; //It's Jan 23ed                Sat  7am

for(var i = 0; i < JANDays.length; i++)
{
    if (thisDayDate == [JANDays[i].day]) {
        if (isSiteDown(JANDays[i].timeStart,JANDays[i].timeEnd)) { 
           showThePage(); 
        } else { 
           console.log('nope');
        }
    }
}

我的问题是我只想对数组执行此操作：

var JANDays = [{day:16, timeStart:"23:00:00"},  //It's Jan 16th Friday 11pm to
               {day:17, timeEnd:"11:00:00"},    //It's Jan 17th                Sat 11am
               {day:22, timeStart:"23:00:00"},  //It's Jan 22nd Friday 11pm to  
               {day:23, timeEnd:"07:00:00"}];   //It's Jan 23ed                Sat  7am

在上面的代码，我想只是对第一天第二天等等等等，一个timeStart和timeEnd

第一天的timeEnd应该在23:59:59保持不变

第二天的timeStart应该在00:00:00保持静态

我不确定如何在IF语句循环中执行此操作，因此将不胜感激。

Answer 1

如果我正确理解...，您想使用以下数组：

var JANDays = [{day:16, timeStart:"23:00:00"},
               {day:17, timeEnd:"11:00:00"},
               {day:22, timeStart:"23:00:00"},
               {day:23, timeEnd:"07:00:00"}];

而不是您当前拥有的那个。

在这种情况下，您可以增加索引i以获得数组中的下一项，例如：

var JANDays = [{day:16, timeStart:"23:00:00"},
               {day:17, timeEnd:"11:00:00"},
               {day:22, timeStart:"23:00:00"},
               {day:23, timeEnd:"07:00:00"}];

for (var i = 0; i < JANDays.length; i++)
{

    if (thisDayDate == JANDays[i].day) {

        // Notice "JANDays[i+1].timeEnd", this will get the timeEnd of the next item in the array
        // (Beware: i+1 could result in undefined)
        if (isSiteDown(JANDays[i].timeStart, JANDays[i+1].timeEnd)) { 
            showThePage(); 
        } else { 
            console.log('nope');
        }
    }
}

---

编辑

---

我仍然不太了解您要寻找的内容，但可能要花一秒钟时间：

var JANDays = [{day:16, timeStart:"23:00:00"},
            {day:17, timeEnd:"11:00:00"},
            {day:22, timeStart:"23:00:00"},
            {day:23, timeEnd:"07:00:00"}];

for (var i = 0; i < JANDays.length; i++)
{
    var day = JANDays[i].day;
    var timeStart = JANDays[i] && JANDays[i].timeStart || "00:00:00";
    var timeEnd = JANDays[i] && JANDays[i].timeEnd;
    var nextTimeEnd = JANDays[i+1] && JANDays[i+1].timeEnd || "23:59:59";
    if (timeEnd) { // This indicates the second day
        console.log(day, timeStart, timeEnd);
    } else {
        console.log(day, timeStart, nextTimeEnd);
    }
}

上面的内容将输出到控制台，例如：

16 "23:00:00" "11:00:00"
17 "00:00:00" "11:00:00"
22 "23:00:00" "07:00:00"
23 "00:00:00" "07:00:00"

每行包括：

1. day ，接着是；
2. timeStart ，后跟；
3. 时间timeEnd

因此，如果天是16，则timeStart和timeEnd将分别为"23:00:00"和"11:00:00" 。

但是，如果天是17，则timeStart和timeEnd为"00:00:00"和"11:00:00" 。

等等

这里的想法是我正在检查循环中是否defined了timeEnd 。

也许对您有帮助？

---

编辑

---

如果是这样，输出应如下所示：

16 "23:00:00" "23:59:59"
17 "00:00:00" "11:00:00"
22 "23:00:00" "23:59:59"
23 "00:00:00" "07:00:00"

那么你可以去：

for (var i = 0; i < JANDays.length; i++)
{
    var day = JANDays[i].day;
    // The code below will check to see if timeStart and timeEnd are defined
    // If they are defined then they will be used,
    // otherwise use the specified value after the pipes (||)
    var timeStart = (JANDays[i] && JANDays[i].timeStart) || "00:00:00";
    var timeEnd = (JANDays[i] && JANDays[i].timeEnd) || "23:59:59";
    if (thisDayDate == day) {
        console.log(day, timeStart, timeEnd);
    }
}

Answer 2

您可以使用map ，然后检查索引以查看它是奇数还是偶数。 像这样：

 var JANDays = [{ day: 16, timeStart: "23:00:00", timeEnd: "24:59:59" }, //It's Jan 16th Friday 11pm to { day: 17, timeStart: "00:00:00", timeEnd: "11:00:00" }, //It's Jan 17th Sat 11am { day: 22, timeStart: "23:00:00", timeEnd: "24:59:59" }, //It's Jan 22nd Friday 11pm to { day: 23, timeStart: "00:00:00", timeEnd: "07:00:00" } ]; //It's Jan 23ed var alt = JANDays.map(function(item,idx) { if (idx % 2) { return { day: item.day, timeStart: item.timeStart }; } else { return { day: item.day, timeEnd: item.timeEnd }; } }); document.getElementById("output").innerHTML = JSON.stringify(alt); 

 <div id="output"></div> 

Answer 3

尝试这个：

 var JANDays = [{day:16, timeStart:"23:00:00", timeEnd:"24:59:59"}, //It's Jan 16th Friday 11pm to {day:17, timeStart:"00:00:00", timeEnd:"11:00:00"}, //It's Jan 17th Sat 11am {day:22, timeStart:"23:00:00", timeEnd:"24:59:59"}, //It's Jan 22nd Friday 11pm to {day:23, timeStart:"00:00:00", timeEnd:"07:00:00"}]; //It's Jan 23ed Sat 7am var output = JANDays.map(function(item, index){ var temp = {}; temp.day = item.day; if(index%2 == 0){ temp.timeStart = item.timeStart; } else{ temp.timeEnd = item.timeEnd; } return temp; }) console.log(output);