const prefix = "get";
const suffix = "Name";

const registry = {
  [`${prefix}Full${suffix}`]: function () {
    return `${this.first} ${this.last}`;
  },
  [`${prefix}Short${suffix}`]: function () {
    return this.first[0] + ". " + this.last;
  },
};

const person = {
  first: "Leonardo",
  last: "Fibonacci",
  ...registry,
};

const key = ["Full", "Short"][1];
console.log(person[`${prefix}${key}${suffix}`]());