Read a .js file from STDIN and write JSON-compatible output (suitable for jq)

js2json.pl

#!/bin/perl

# Description:
# Read a .js file from STDIN and write JSON-compatible output (suitable for jq)

# The input file in the format ...
#   var data = { "run": [...
# cannot be read by jq directly. This script transforms a javascript file to json output.

use strict;
use warnings;

$| = 0;

my $level = 0;
my $delim = "";

while ( <> ) {

    # Remove var xxx = from js
    s/^\s*var
       \s*
       \S+
       \s*=\s
     //x;

     my $round = 0;

     while ( length > 0 ) {

         # { and }
         if ( s/^\{\s*// ) {
            print $delim; $delim = "";
            print " " x (2*$level);
            print "{";
            print "\n";
            $level++;
         }
         if ( s/^\}\s*(,?)\s*// ) {
            $level--;
            print "}";
            $delim = $1;
         }
         # [ and ]
         if ( s/^\[\s*// ) {
            print $delim; $delim = "";
            print " " x (2*$level);
            print "[";
            print "\n";
            $level++;
         }
         if ( s/^\]\s*(,?)\s*// ) {
            $level--;
            print "]";
            $delim = $1;
         }
         # "bla": ...
         if ( s/^("[^"]+")\s*:\s*//i ) {
            print $delim; $delim = "";
            print "\n";
            print " " x (2*$level);
            print "$1: ";
         }
         # "data",
         if ( s/^("[^"]*")\s*(,?)\s*//i ) {
            print $delim; $delim = "";
            print "$1";
            $delim = $2;
         }
         # 'data',
         if ( s/^'([^']*)'\s*(,)\s*//i ) {
            print $delim; $delim = "";
            my $text = $1;
            $delim = $2;
            $text =~ s/"/\\"/g;  # Replace " by \"
            print "\"$text\"";
         }
         # number data
         if ( s/^([0-9.]+)\s*(,?)\s*//i ) {
            print $delim; $delim = "";
            print "$1";
            $delim = $2;
         }

         # Terminates program if there seems to be an endless loop
         # Maybe a problem with very long lines
         $round++;
         #print $round;
         die if $round > 99990;

     }

}