postgres阵列和导轨4 erb

Question

i have a view in my postgres database that returns an array on my frequencies column. unfortunately, it sometimes returns values like {NULL} (due to the raw data).

in my rails view, i have something like:

dataset = [
    <% @item.each do |i| %>
        {   
            name: "<%= i.device %>" 
            lng: <%= i.longitude %> 
            lat: <%= i.latitude %>
            frequencies: <%= i.frequencies.to_s.html_safe %>
        },
    <% end %>
]

which appears to work great - except when it reaches a record that contains {NULL} :

in the javascript console it shows:

Uncaught ReferenceError: nil is not defined 

and in the html it shows:

  ...
  }, {
    name: "blah",
    lng: -122.2,
    lat: 37.4,
    frequencies: [nil]
  }, { 
  ...

i could fix this by iterating through the list in the controller, but i think this would be rather long winded (and a waste of cycles).

is there a way i can get the erb to output the 'correct' [] in (instead of [nil] ) json when it's null?

Answer 1

Try this:

 <%= i.frequencies.compact %>

compact example:

 [nil].compact #=> []
 [1,2, nil, 3, nil].compact  #=> [1,2,3]