momentjs startOf不适用于现有的日期对象 [英] momentjs startOf does not work on existing date object

问题描述

我正在尝试利用瞬间来开始新的一天.我得到以下不同的结果:

I'm trying to use moment to get the start of a day. I get different results with the following:

moment().startOf('day'); //good
moment(new Date()).startOf('day'); //this does not work!

小提琴: https://jsfiddle.net/y1of77wx/

实际情况是，我在将日期对象作为参数的函数中执行此操作:

The practical case is that I'm doing this in a function that takes in a date object as an argument:

function doWork(dt) {
   return moment(dt).startOf('day');
}

我确定解决方案很简单，但是我只是缺少一些东西.

I'm sure the solution is simple but I'm just missing something.

推荐答案

我建议使用 format() 以显示矩对象的值.

I suggest to use format() to display the value of a moment object.

内部属性指南指出:

矩对象具有几个内部属性，这些属性以_为前缀.

最常查看的内部属性是_d属性，其中包含Moment包装器的JavaScript Date.通常，开发人员会对控制台输出_d的值感到困惑.

The most commonly viewed internal property is the _d property that holds the JavaScript Date that Moment wrappers. Frequently, developers are confused by console output of the value of _d.

...

要打印出Moment的值，请使用.format()，.toString()或.toISOString()

To print out the value of a Moment, use .format(), .toString() or .toISOString()

以下是显示正确结果的代码段:

Here a snippet showing the correct results:

console.log(moment().startOf('day').format());
console.log(moment(new Date()).startOf('day').format());

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.18.1/moment.min.js"></script>

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