This is a port of https://github.com/rwdaigle/heroku-log-parser to Javascript ES6 for Node.js. The interface is slightly different but the logic is essentially the same.
> let incomingMessage = "156 <40>1 2012-11-30T06:45:26+00:00 heroku web.3 d.73ea7440-270a-435a-a0ea-adf50b4e5f5a - Starting process with command `bundle exec rackup config.ru -p 24405`"
> let herokuLogParser = require('../heroku-log-parser.js')
> let parsedMessage = herokuLogParser.parse(incomingMessage)
> parsedMessage
[ { priority: 40,
syslog_version: 1,
emitted_at: '2012-11-30T06:45:26+00:00',
hostname: 'heroku',
appname: 'web.3',
proc_id: 'd.73ea7440-270a-435a-a0ea-adf50b4e5f5a',
msg_id: null,
structured_data: null,
message: 'Starting process with command `bundle exec rackup config.ru -p 24405`',
original: '<40>1 2012-11-30T06:45:26+00:00 heroku web.3 d.73ea7440-270a-435a-a0ea-adf50b4e5f5a - Starting process with command `bundle exec rackup config.ru -p 24405`' } ]