Update some of the exercises

examples/characters/src/person.js

@@ -0,0 +1,17 @@
+import { v4 as id } from 'uuid';
+
+export class Person {
+  constructor(firstName, lastName) {
+    if (!firstName || !lastName) {
+      throw new Error('First name and last name are required');
+    }
+
+    this.id = 'person-' + id();
+    this.firstName = firstName;
+    this.lastName = lastName;
+  }
+
+  get fullName() {
+    return `${this.firstName} ${this.lastName}`;
+  }
+}