BUG: Inconsistent delay property

Created by: tsebas

Description

When a job is created with queue.add with the delay param in opts, the resulting job has the delay property with the assigned value. However, in the queue processor, the job that comes in has the corret delay value in the opts object, whilst the delay property has 0.

Minimal, Working Test code to reproduce the issue.

const bull = require('bull');

const q = new bull('queue', {
	redis: {host: 'localhost', port: 6380, password: null},
});

q.process(job => {
	console.log('process', job.delay, job.opts.delay);
});

q.add({}, {delay: 1}).then(job => console.log('add', job.delay, job.opts.delay));

Bull version

"bull": "^3.14.0"

Additional information

The above code generates the following output. I added a console.log on Job.fromJSON function in bull/lib/job.js:576

add 1 1
json { name: '__default__',
  data: '{}',
  opts: '{"delay":1,"attempts":1,"timestamp":1598439486198}',
  timestamp: '1598439486198',
  delay: '0',
  priority: '0',
  processedOn: '1598439486213' }
process 0 1

I didn't fully debug the code to understand where the most appropriate fix would go, but I suspect the only actually problematic line is bull/lib/job.js:588 job.delay = parseInt(json.delay);. Before this line, the job.delay is correctly built form the constructor.