javascript - Moment JS 给定月份的开始和结束

Question

我需要计算给定 year=2014 和 month=9(2014 年 9 月)的 JS 日期。

我试过这个:

var moment = require('moment');
var startDate = moment( year+'-'+month+'-'+01 + ' 00:00:00' );
            var endDate = startDate.endOf('month');
            console.log(startDate.toDate());
            console.log(endDate.toDate());

两个日志显示:

Tue Sep 30 2014 23:59:59 GMT+0200 (CEST)
Tue Sep 30 2014 23:59:59 GMT+0200 (CEST)

结束日期正确，但...为什么开始日期不正确？

Answer 1

那是因为endOf改变原始值。

相关引用:

Mutates the original moment by setting it to the end of a unit of time.

这是一个示例函数，可以为您提供所需的输出:

function getMonthDateRange(year, month) {
    var moment = require('moment');

    // month in moment is 0 based, so 9 is actually october, subtract 1 to compensate
    // array is 'year', 'month', 'day', etc
    var startDate = moment([year, month - 1]);

    // Clone the value before .endOf()
    var endDate = moment(startDate).endOf('month');

    // just for demonstration:
    console.log(startDate.toDate());
    console.log(endDate.toDate());

    // make sure to call toDate() for plain JavaScript date type
    return { start: startDate, end: endDate };
}

引用资料:

• endOf()
• clone()
• Date from object