I'm trying to use Lodash to merge object A into object B, but the trouble I am having is that object A has some undefined values and I want these to be copied over to object B.

Lodash docs for \_.merge() says:

**"Recursively merges own enumerable properties of the source object(s), that don't resolve to undefined into the destination object."**

Is there another function that can do this, or can it be easily overwritten?

**EDIT A:**

Sample input:

```
A = {
  name: "Bob Smith",
  job: "Racing Driver",
  address: undefined
}

B = {
  name: "Bob Smith",
  job: "Web Developer",
  address: "1 Regent Street, London",
  phone: "0800 800 80"
}

```

Expected Output

```
B = {
  name: "Bob Smith",
  job: "Racing Driver",
  address: undefined,
  phone: "0800 800 80"
}

```

**EDIT B:**

Just to confirm, it needs to be a "deep" merge. object may contain nested objects.