why don't we have the 'find my iphone' app on mac app store?

why hasn't apple develped the ' find my iPhone ' app for mac systems? i find it hard to consume that after buying a macbook air, that if i lose my iphone 5, i wont be able to track the location of it, i really shouldn't have to buy an iPad surely? not that i don't take car of my iPhone or think i will lose it, but it would be nice to know if the unfortunate happened, i could find it.