Validators are implemented for each workflow execution status Validators are applied in production code

Script
  var validators = {
    'init': function () { return true },
    'created': function (wf, _) {
      return wf.status === 'created'
    },
    'submitted': function (wf, _) {
      return wf.status === 'submitted'
    },
    'inProgress': function (wf, _) {
      return wf.status === 'inProgress'
    },
    'executing': function (wf, _) {
      return wf.status === 'inProgress'
    },
    'completed': function (wf, _) {
      return wf.status === 'completed'
    },
    'failed': function (wf, _) {
      return wf.status === 'failed'
    },
    'cancelled': function (wf, _) {
      return wf.status === 'cancelled'
    }
  }