TypeScript記号マスター

記号が含まれた短いコードセンテンスでタイピング練習。TypeScriptの構文に慣れましょう。

type Greet = (name: string) => string;
const add = (a: number, b: number) => a + b;
interface User { name: string; age: number; }
const arr: number[] = [1, 2, 3, 4, 5];
const obj = { key: 'value', count: 10 };
function multiply(x: number, y: number): number {}
const isValid = value !== null && value !== undefined;
const result = data?.user?.profile?.name ?? 'Guest';
const numbers = [...arr1, ...arr2, ...arr3];
const { name, age, ...rest } = user;
type Result<T> = { data: T } | { error: string };
const promise = async (): Promise<void> => {};
const callback = (err?: Error, data?: any) => {};
if (condition) { doSomething(); } else { doOther(); }
const ternary = isActive ? 'yes' : 'no';
for (let i = 0; i < arr.length; i++) {}
array.map((item) => item.value).filter((v) => v);
const regex = /^[a-zA-Z0-9]+$/g;
obj['key'] = value || defaultValue;
export default class MyClass extends BaseClass {}