在多維JavaScript對象中查找最大/最小日期

Question

從下面的對象中查找最早開始日期和最晚結束日期的最簡單方法是什么？

（對不起-我意識到已經有很多類似的問題，但是我的JS技能很差，而且我無法將任何解決方案應用於我自己的數據。因此，有了這樣的示例，代碼示例肯定會幫我解決任何問題-謝謝!!）

var ganttData = [
    {
        "id": 123456,
        "name": "Sample Project",
        "start": new Date(2010,11,6),
        "end": new Date(2011,0,6),
        "status": "Not Started",
        "phase": [
            {
                "id": 123457,
                "name": "Sample Phase",
                "start": new Date(2010,11,6),
                "end": new Date(2010,11,13),
                "status": "Not Started",
                "task": [
                    {
                        "id": 123458,
                        "name": "Sample Task",
                        "start": new Date(2010,11,6),
                        "end": new Date(2010,11,8),
                        "status": "Not Started"
                    }
                ]
            },
            {
                "id": 123459,
                "name": "Another Phase",
                "start": new Date(2010,11,13),
                "end": new Date(2011,0,20),
                "status": "Not Started"
            }
        ]
    }
]

Answer 1

您可以簡單地遞歸遍歷樹

var max = new Date(-100000000*86400000);
var min = new Date( 100000000*86400000);

function compare(key,value) {
    if (key == "start" && value < min)
        min=value;
    else if (key == "end" && value > max)
        max=value;
}

function traverse(obj, fun) {
    for (prop in obj) {
        fun.apply(this,[prop, obj[prop]]);   
        if (typeof(obj[prop]) == "object") {
            traverse(obj[prop], fun);
        }
    }
}

traverse(ganttData, compare);

> max
Thu Jan 20 2011 00:00:00 GMT+0100 (W. Europe Standard Time)
> min
Mon Dec 06 2010 00:00:00 GMT+0100 (W. Europe Standard Time)

上面的方法一直有效，直到您將開始和結束從Date更改為string為止。 現在你必須做這樣的事情

arr = "2010,11,13".split(",");
date = new Date(arr[0], arr[1], arr[2]);

比較之前。

我從JavaScript參考中獲得了相反的最小和最大日期 。

Answer 2

function getEarliestAndLatest(ganttData) {
    var earliest = ganttData.start,
        latest   = ganttData.end,
        phase,
        task;
    for (var i = 0, countPhases = ganttData.phase.length; i < countPhases; i++) {
        phase = ganttData.phase[i];
        if (phase.start < earliest) {
            earliest = phase.start;
        }
        if (phase.end > latest) {
            latest = phase.end;
        }
        if (typeof phase.task !== 'undefined') {
            for (var j = 0, countTasks = phase.task.length; j < countTasks; j++) {
                task = phase.task[j];
                if (task.start < earliest) {
                    earliest = task.start;
                }
                if (task.end > latest) {
                    latest = task.end;
                }
            }
        }
    }
    return { earliest: earliest, latest: latest };
}