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)'test-basic-coupon') .done( function (price) { console.log(price) }) }))