Simple Erlang views for CouchDB

simple-view-no-null.erl

%% this is an exact match for the original JS function

fun({Doc}) ->
    case proplists:is_defined(<<"diet">>, Doc) of
        true ->
            Emit(proplists:get_value(<<"diet">>, Doc), 1);
        false ->
            ok
    end
end.

simple-view-with-anon-func.erl

%% This is also an exact function, but uses an inline
%% anonymous function just to show how additional functions
%% can be defined and included

fun({Doc}) ->
    Foo = fun(D) ->
        proplists:get_value(<<"diet">>, D)
    end,
    case proplists:is_defined(<<"diet">>, Doc) of
        true ->
            Emit(Foo(Doc), 1);
        false ->
            ok
    end
end.

simple-view.erl

%% This version will emit (null, 1) for docs that do not define diet
%% as such it is not a faithful reproduction of the original view,
%% but it will not crash on docs missing diet.

fun({Doc}) ->
    Emit(proplists:get_value(<<"diet">>, Doc, null), 1)
end.

simple-view.js

// The simplest of map views in JavaScript. 90% of views look like this.
function(doc)
{
    if(doc.diet)
    {
        emit(doc.diet, 1);
    }
}