Deb packaging fails with Uglifier::Error: Unexpected token: name (id)

[tristanrobert]

https://github.com/theforeman/foreman-packaging/pull/6447

https://ci.theforeman.org/job/packaging_build_deb_plugin/arch=x86,label=debian,os=bionic/721/console

16:06:10 Uglifier::Error: Unexpected token: name (id). To use ES6 syntax, harmony mode must be enabled with Uglifier.new(:harmony => true). 16:06:10 -- 16:06:10  19 var id = $(item).attr('id'); 16:06:10  20 var pattern = /(host_compute_attributes_volumesattributes||compute_attribute_vm_attrs_volumesattributes)(\d+)_/i; 16:06:10  21 pattern_a = pattern.exec(id); 16:06:10  22 var index = patterna[2]; 16:06:10  23 return index; 16:06:10  24 } 16:06:10  25 16:06:10  26 function volumeId(type,index){ 16:06:10  =>  let id = '#volume' + type + '_' + index; 16:06:10  28 return id; 16:06:10  29 } 16:06:10  30 16:06:10  31 function enableField(id) { 16:06:10  32 $(id).show(); 16:06:10  33 $(id).removeAttr('disabled'); 16:06:10  34 } 16:06:10  35