Gets the length of the JavaScript object, gets the nth attribute of the JavaScript object __java

The object in JavaScript does not provide a method of length

However, the Object.keys can be converted through the array.

The Object.keys () method returns an array of property names for all enumerable properties of a given object, in which the order of the property names in the array is the same as the order returned when the object is traversed using the for-in loop (the main difference is for-in It also traverses an enumerable property that an object inherits from its prototype chain.

Want to get the nth attribute to find the corresponding element directly using the returned array index