在使用地图之前检查数组：

Check the array before using map:

arr && arr.map()

OR，

arr && arr.length && arr.map() // if you want to map only if not empty array

OR，

我们甚至可以像这样使用（由 devserkan 评论）：

We can even use like this (as commented by devserkan):

(arr || []).map()

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根据您的评论：

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As per your comment:

我希望有一个安全的导航操作符，比如C＃（arr？.map（））

I wish there was a safe navigation operator like with C# (arr?.map())

是的，很明显。这在JavaScript中称为可选链接，仍在提案中。如果它被接受，那么你可以这样使用：

Yes, obviously. This is called optional chaining in JavaScript which is still in proposal. If it is accepted, then you may use like this:

arr?.map()

您可以在中看到它您可以使用 babel预设stage1 的舞台1

You can see it in staging 1 for which you may use babel preset stage1

但显然，除了检查数组长度外，您的要求将无法满足：

But obviously, except the checking array length, your requirement will not be fulfilled:

这会导致错误，因为当然，数组的第一个索引是未定义的。

This results in an error because, of course, the first index of the array is undefined.

所以，我建议您使用：

arr && arr.length && arr.map()