stream.jq

# same as fromstream but with a prefix level, outputs [$prefix_path, $json_value], ...
# Usage:
# cat big | jq -L . --stream -n 'include "stream"; reduce fromstream(inputs; 1) as $pv ({}; $pv as [$p, $v] | .[$v.type] += 1)'

def streaks_by(f; g):
  foreach ((g | ["v", .]), ["end"]) as $o (
    { acc: null
    , fv: null
    , emit: null
    };
    ( .emit = null
    | $o as [$t, $v]
    | ($v | f) as $fv
    | if $t == "end" then .emit = .acc
      elif .acc == null then .acc = [$v]
      else
        if $fv == .fv then .acc += [$v]
        else
          ( .emit = .acc
          | .acc = [$v]
          )
        end
      end
    | .fv = $fv
    );
    .emit // empty
  );

def fromstream(g; $level):
  ( streaks_by(
      .[0][0:$level];
      g
    )
  | [ .[0][0][0:$level]
    , fromstream(.[] | .[0] |= .[$level:])
    ]
  );