Javascript 如何测试变量是否为 Moment.js 对象？
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How to test if a variable is a Moment.js object?
提问by Brett DeWoody
My application has an HTML form with some inputs populated from the backend and other inputs being entered by the user (in a timeinput). An onChangefunction runs through each input when the user changes a value.
我的应用程序有一个 HTML 表单，其中一些输入从后端填充，其他输入由用户time输入（在输入中）。的onChange功能，当用户改变一个值贯穿每个输入。
The inputs populated from the backend are converted to momentobjects, the user-entered dates are mere strings. This means the onChangefunction encounters some momentobjects, and some strings. I need to know which inputs are momentobjects and which aren't.
从后端填充的输入被转换为moment对象，用户输入的日期只是字符串。这意味着该onChange函数会遇到一些moment对象和一些字符串。我需要知道哪些输入是moment对象，哪些不是。
What's the recommended method for testing if a variable is a momentobject?
测试变量是否为moment对象的推荐方法是什么？
I've noticed momentobjects have a _isAMomentObjectproperty but I'm wondering if there's another way to test if a variable is a momentobject.
我注意到moment对象有一个_isAMomentObject属性，但我想知道是否有另一种方法来测试变量是否是moment对象。
Another option I've tried is calling momenton the variable regardless. This converts the stringvariables to momentobjects and doesn't seem to effect existing momentobjects.
我尝试过的另一个选择是moment无论如何调用变量。这会将string变量转换为moment对象，并且似乎不会影响现有moment对象。
采纳答案by Jared Smith
Moment has an isMomentmethodfor just such a purpose. It is not particularly easy to find in the docs unless you know what to look for.
Moment 有一种isMoment方法可以达到这样的目的。除非您知道要查找的内容，否则在文档中并不是特别容易找到。
It first checks instanceofand then failing that (for instance in certain subclassing or cross-realm situations) it will test for the _isAMomentObjectproperty.
它首先检查instanceof然后失败（例如在某些子类化或跨领域情况下）它将测试_isAMomentObject属性。
回答by Niels Heisterkamp
You can check if it is an instanceofmoment:
您可以检查是否是instanceof片刻：
moment() instanceof moment; // true
回答by Fabien Sartori
moment() instanceof moment;
时刻（）实例时刻；
will always be true, because if you have
将永远是真的，因为如果你有
- moment(undefined) instanceof moment
- moment("hello") instanceof moment
- 时刻（未定义）时刻实例
- 瞬间（“你好”）瞬间的实例
you are always creating a moment object. So the only way is to check like this
你总是在创造一个时刻对象。所以唯一的方法是像这样检查
- moment(property).isValid()
- 时刻（属性）。isValid（）
