This is not "invalid JSON", but simply Javascript code. Either you write a proper parser which parses/preprocesses/handles those expressions for you, or you run that code through a Javascript interpreter and then dump the result as JSON.

#!/usr/bin/perl

$str=' publish_date: new Date(1431654084199) ' ;
$str =~ s/:\s*new Date\((\d+)\)\s*/&epoch2timestring($1)/ge;
print $str . "\n";

sub epoch2timestring{
    my ($e) = @_;
    $e=~s/.{3}$//; # eat 3 last digits
    my $result = scalar localtime($e);
    return ': "' . $result . '" '; # gmtime() ?
}
[download]

prints:

 publish_date: "Fri May 15 03:41:24 2015"

Please read my node. showParams cannot be evalled because of syntax errors. If a data stream is emitted with syntax errors of this magnitude, the content had better be valuable the fixes you make are going to be incredibly fragile.

For example, in order to clean showParams, you need to detect unescaped quotes and escape them. For the sample you could run

my $str = 'showParams: "{"revertType":null,"refresh":false,"checkpoint
+":false,"sheetName":"","unknownParams":"zone_id=6290&ac=a9aef098062f9
+646bd1638d0c6054c7b&account_id=62&Start_Date=2016-07-27&End_Date=2016
+-08-03","layoutId":""}"';
while ($str =~ /(?<!\\)"\s*\{\s*("(?:(?!\}").)*)\}"/) {
    substr($str, $-[1], $+[1] - $-[1]) =~ s/(?=["\\])/\\/g;
}
[download]

but good luck maintaining that.

---

#11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.

Well, that is the thing everyone is pointing out. You can either write a pre-parser that fixes it into standard JSON, then read it with the JSON modules, or parsing it yourself (which could mean you will have to implement much more).

From JSON#Data_portability_issues

Despite the widespread belief that JSON is a strict subset of JavaScript, this is not the case. Specifically, JSON allows the Unicode line terminators U+2028 LINE SEPARATOR and U+2029 PARAGRAPH SEPARATOR to appear unescaped in quoted strings, while JavaScript does not. .

In "Unsupported native data types" Wikipedia specifically states for Date() that there are some de facto standards, e.g., converting from Date to String, but none universally recognized. This JSON is "weird" like that.

So each line is an identifier: thing where thing can be:

(something that must be evaluated in Javascript itself)

"{"...."}" a hash

"a string"

false a boolean

new Date(... a date

Strings and booleans are json already, the others, not that much...

#!/usr/bin/perl 
use strict;
use warnings;
use JSON::PP;

my $json_text = '';
# read string from __DATA__
while(<DATA>){ $json_text .=$_ }

# work around javascript eval's
$json_text =~ s/^(\w+:) \(.*$/"$1": 0, /gm;
# fix date
$json_text =~ s/:\s*new Date\((\d+)\)\s*/&epoch2timestring($1)/ge;
# fix hashes
$json_text =~ s/^(\w+:) "{(.*)}",/"$1": {$2}, /gm;
# fix remaining fields (should be quotes)
$json_text =~ s/^(\w+):/"$1":/gm;


my $perl_scalar = JSON::PP->new->relaxed->allow_singlequote->allow_bar
+ekey->loose->decode($json_text);

use Data::Dumper; 
die Dumper($perl_scalar);

sub epoch2timestring{
        my ($e) = @_;
        $e=~s/.{3}$//; # eat 3 last digits
        my $result = scalar localtime($e);
        return ': "' . $result . '" '; # gmtime() ?
}


__DATA__
{
is_touch: ('ontouchstart' in window), 
repository_urls: ["publisher_view2_videossp/PublisherView_videossp2"],
origin_repository_url: "publisher_view2_videossp/PublisherView_videoss
+p2",
workbook_repo_url: "publisher_view2_videossp",
publish_date: new Date(1431654084199),
tabs_allowed: false,
showTabsWorkbook: true,
mobile_app_cookie: "",
current_project_id: "7",
current_sheet_name: "",
current_sheet_type: "", 
current_workbook_name: "publisher_view2_videossp",
current_workbook_id: "1548",
current_view_id: "2713",
sheetId: "PublisherView_videossp2",
showParams: "{"revertType":null,"refresh":false,"checkpoint":false,"sh
+eetName":"","unknownParams":"zone_id=6290&ac=a9aef098062f9646bd1638d0
+c6054c7b&account_id=62&Start_Date=2016-07-27&End_Date=2016-08-03","la
+youtId":""}",
stickySessionKey: "{"isAuthoring":false,"lastUpdatedAt":1470316180805,
+"workbookId":1548}",
}
[download]

edit: added missing "my" that got lost in copy/paste, now it runs...