Using An Interface In Typescript

interface PlushyDetails {
  name: String
  animal: String
  price: Number
}

class Plushy {
  details: PlushyDetails

  constructor(details) {
    this.details = details
  }

  listingDetails() {
    return `${this.details.name || "Name"} the ${this.details.animal || "Animal"}: $${this.details.price || 12.34}`
  }
}

let grove = new Plushy({name: "Grove", animal: "Duck"});
let ragu = new Plushy({name: "Ragu", animal: "Dragon", price: 16.23})
let blank = new Plushy({});

console.log(grove.listingDetails());
console.log(ragu.listingDetails())
console.log(blank.listingDetails())

Output:

"Grove the Duck: $12.34"
"Ragu the Dragon: $16.23"
"Name the Animal: $12.34"