The easiest way to access an object's single own property?

问题

I have an object which will only have one property (own property). What is the easiest way to access that property's value?

Something like:

value = obj[<firstProperty>];

I know I can write a function or a for loop to do this but am asking if there is a shorter way.

for (p in obj) {
    if (obj.hasOwnProperty(p)) {
       value = obj[p];
    }
}

I won't know the name of the property up front. I only know that there will only be one property directly on the object.

回答1:

something like

var value = obj[ Object.keys(obj)[0] ];

getting the keys with Object.keys and the first (and only) key with [0]

回答2:

This should work.

var keys = Object.keys(obj);
var value = obj[keys[0]];

We can make it shorter

var value = obj[Object.keys(obj)[0]];

来源：https://stackoverflow.com/questions/29439905/the-easiest-way-to-access-an-objects-single-own-property