Can't add plan specific coupon using Recurly.js Pricing object

The coupon can't be applied until after the plan is applied only because it's a plan-specific coupon. Therefore it can't be applied to a checkout without a subscription/plan.
 
In order to add it, the plan must be done before adding the coupon. The following code accomplishes this goal.
 

const checkoutPricing = recurly.Pricing.Checkout();
checkoutPricing
  .subscription(recurly.Pricing.Subscription()
  .plan('basic', {quantity: 1})
  .catch(function (err){ console.log('subscription error',
  {err})})
  .done(function(price) {
    console.log(price)
    checkoutPricing.coupon('test-basic-coupon')
    .done( function (price) {
      console.log(price)
    })
    }))