Displaying job status in a jQuery Datatable
First of all, you may benefit from the fact that in Coffee (and in JS, too), the following code

if condition
  variable = value


can be expressed simpler as

variable = condition &amp;&amp; value


Therefore, the declaration of the table may be written as

table = $('#dtable').length &amp;&amp; $('#dtable').DataTable()


Later in the code, you should not check again for the $('#dtable').length but you should check if the table has a value, possibly with the existential operator. For example, replace the

if $('#dtable').length
    table.cell('#td_5_' + data.job_id).data wait_status


with

table?.cell('#td_5_' + data.job_id).data wait_status


I don't know what the detail_status is but I suppose it is a string selector. Therefore, you don't need to check if it is available in the DOM. JQuery will do nothing if there is no such element, so you can safely call $(detail_status).html wait_status without checking for its length. The same goes for e.g. removeClass method.

You can also use Coffee's string interpolation and replace the "#row" + data.job_id with "#row#{data.job_id}" (and similar).

Last but not least, try replacing multiple conditions like if data.status != "Created" and data.status != "Job Deleted" and data.status != "Scan Complete" with one statement with the in operator, i.e. if data.status not in ['Created', 'Job Deleted', 'Scan Complete'].