Get the intersection of an arbitrary number of json files with jq

intersect.sh

#!/usr/bin/env bash

function intersectJson {
  echo $* | \
  jq -nS '
    def intersect:
      .[0] as $a |
      .[1] as $b |
      if ($a | type) == "object" then
        if ($b | type) == "object" then
          $a | reduce keys[] as $k ( {} ;
            if $k | in($b) then
              . + { $k: ( [ $a[$k], $b[$k] ] | intersect ) }
            end
          ) | with_entries(select(.value != null and .value != {}))
        else
          null
        end
      elif ($a | type) == "array" then
        if ($b | type) == "array" then
          [ $a, $b ] | transpose | map(intersect)
        else
          null
        end
      elif $a == $b then
        $a
      else
        null
      end;
    input as $first |
    [ inputs ] |
    reduce .[] as $i ( $first ; [ ., $i ] | intersect )
  '
}

intersectJson $(cat $*)

# vim:ts=8:sts=2:sw=2:et