Doesn't merge property by descriptor if property returns `undefined`

[adque]

There is a bug when merging by descriptor. When merging a property that returns undefined, the property will not be merged. This is problematic since the value that property returns may later change.

Example:

var store = {};
var merged = Object.merge({}, { get value() { return store['x'] } }, { descriptor: true });
store['x'] = "testing...";

// logs undefined instead of "testing..." because the `value` property is not merged
// because it returns undefined at the time it is merged
console.log(merged.value);

var descriptor = Object.getOwnPropertyDescriptor(merged, 'value');
console.log(descriptor);  // logs undefined

[andrewplummer]

Hi, sorry for taking so long to respond to this. Unfortunately this is as the method is specced right now. Any properties that are undefined will not be merged. I agree that this is not ideal for situations like this and will have a look in the next major version about ways to resolve. I should also add that the merge method is entirely too complicated right now and doesn't accomplish the main use cases for the complexity required to use. Merging non-enumerable properties as well as merging property descriptors will likely be moved out of the main package into a plugin. At that point I'll revisit the method to make sure it's easier to use.

Thanks!