// src/components/Hello.tsx import * as React from "react"; export interface Props { name: string; enthusiasmLevel?: number; } function Hello({ name, enthusiasmLevel = 1 }: Props) { if (enthusiasmLevel <= 0) { throw new Error("You could be a little more enthusiastic. :D"); } return (
Hello {name + getExclamationMarks(enthusiasmLevel)}
); } export default Hello; // helpers function getExclamationMarks(numChars: number) { return Array(numChars + 1).join("!"); }