Validate a Firebase Key is an integer

Question

Here is the database schema:

Here are the rules:

\"notifications\": {
   \"$year\": {
      \".read\": \"false\",
      \".write\": \"!data.         


        

Answer 1

To validate that a key is a number:

{
  "$key": {
     ".validate": "$key.matches(/^[0-9]+$/)"
  }
}

But please read about array-like behaviors in Firebase. Hint: probably use a prefix like "y2015", "m12", etc. to avoid some unexpected results with using numbers.