firebase-admin node sdk: Why admin.database is both a function and property?

Question

在firebase-admin sdk中，没有人知道如何/为什么可以将admin.database作为函数admin.database()和属性/命名空间（即admin.database.ServerValue吗？

Answer 1

In JavaScript, functions can have properties.

> function x() {}
undefined
> x
[Function: x]
> x.prop = 1
1
> x
{ [Function: x] prop: 1 }
>

Credit goes to Doug Stevenson for pointing it out to me on the firebase slack channel. Thanks Doug!