Google Maps API warning: NoApiKeys
Solution 1:
Creating and using the key is the way to go. The usage is free until your application reaches 25.000 calls per day on 90 consecutive days.
BTW.: In the google Developer documentation it says you shall add the api key as option {key:yourKey} when calling the API to create new instances. This however doesn't shush the console warning. You have to add the key as a parameter when including the api.
<script src="https://maps.googleapis.com/maps/api/js?key=yourKEYhere"></script>
Get the key here: GoogleApiKey Generation site
Solution 2:
A key currently still is not required ("required" in the meaning "it will not work without"), but I think there is a good reason for the warning.
But in the documentation you may read now : "All JavaScript API applications require authentication."
I'm sure that it's planned for the future , that Javascript API Applications will not work without a key(as it has been in V2).
You better use a key when you want to be sure that your application will still work in 1 or 2 years.