(updated ) by

argument error, :erlang.byte_size

This error comes when you don’t pass a binary to Elixir string operators.

  def remove_hash("#" <> _ = channel)  do
   	channel
  end

If you do:

remove_hash('#rockerboo')

you’ll get an error.

** (ArgumentError) argument error
    :erlang.byte_size('#rockerboo')

Needs to be:

remove_hash("#rockerboo")

iex(1)> :erlang.byte_size('rockerboo')
** (ArgumentError) argument error
    :erlang.byte_size('rockerboo')
iex(1)> :erlang.byte_size("rockerboo")
9