在多维JavaScript对象中查找最大/最小日期

Question

从下面的对象中查找最早开始日期和最晚结束日期的最简单方法是什么？

（对不起-我意识到已经有很多类似的问题，但是我的JS技能很差，而且我无法将任何解决方案应用于我自己的数据。因此，有了这样的示例，代码示例肯定会帮我解决任何问题-谢谢!!）

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

您可以简单地递归遍历树

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，直到您将开始和结束从Date更改为string为止。 现在你必须做这样的事情

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

比较之前。

我从JavaScript参考中获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 };
}