with javascript_semantics
requires("1.0.6") -- (or use the pre-1.0.6 code below)
constant A = {{27,"Jonah"},
              {18,"Alan"},
              {28,"Glory"},
              {18,"Popeye"},
              {28,"Alan"}},
         B = {{"Jonah","Whales"},
              {"Jonah","Spiders"},
              {"Alan", "Ghosts"},
              {"Alan", "Zombies"},
              {"Glory","Buffy"}},
        jA = 2, -- (join A index)
        jB = 1, -- (join B index)
        MB = new_dict()
sequence C = {}
for b in B do
    object key = b[jB],
          data = getdd(key,{},MB,true) -- 1.0.6+
    data = append(data,b)
    putd(key,data,MB)
end for
for a in A do
    for d in getdd(a[jA],{},MB) do
        C = append(C,{a,d})
    end for
end for
destroy_dict(MB)
pp(C,{pp_Nest,1})