// Example TypeScript file: example1.ts
// This file contains a variety of TypeScript constructs for testing purposes.
// Update marker 1
(() => {
// --- Interfaces ---
interface User {
id: number;
name: string;
email: string;
isActive: boolean;
roles: string[];
}
interface Product {
id: number;
name: string;
price: number;
tags?: string[];
}
// --- Enums ---
enum LogLevel {
DEBUG = 'debug',
INFO = 'info',
WARN = 'warn',
ERROR = 'error',
}
// --- Classes ---
class Logger {
private level: LogLevel;
constructor(level: LogLevel) {
this.level = level;
}
log(message: string, level: LogLevel = LogLevel.INFO) {
if (this.shouldLog(level)) {
console.log(`[${level}] ${message}`);
}
}
private shouldLog(level: LogLevel): boolean {
const order = [LogLevel.DEBUG, LogLevel.INFO, LogLevel.WARN, LogLevel.ERROR];
return order.indexOf(level) >= order.indexOf(this.level);
}
}
// Update marker 2
// --- Functions ---
function getUserById(users: User[], id: number): User | undefined {
return users.find(u => u.id === id);
}
function calculateTotal(products: Product[]): number {
return products.reduce((sum, p) => sum + p.price, 0);
}
function filterActiveUsers(users: User[]): User[] {
return users.filter(u => u.isActive);
}
function addRoleToUser(user: User, role: string): User {
return { ...user, roles: [...user.roles, role] };
}
// --- Generics ---
function identity<T>(value: T): T {
return value;
}
function mapArray<T, U>(arr: T[], fn: (item: T) => U): U[] {
return arr.map(fn);
}
// --- Utility Types ---
type ReadonlyUser = Readonly<User>;
type PartialProduct = Partial<Product>;
// --- Example Data ---
const users: User[] = [
{ id: 1, name: 'Alice', email: 'alice@example.com', isActive: true, roles: ['admin'] },
{ id: 2, name: 'Bob', email: 'bob@example.com', isActive: false, roles: ['user'] },
{ id: 3, name: 'Charlie', email: 'charlie@example.com', isActive: true, roles: ['user', 'editor'] },
];
// Update marker 3
const products: Product[] = [
{ id: 1, name: 'Laptop', price: 1200, tags: ['electronics', 'computers'] },
{ id: 2, name: 'Phone', price: 800 },
{ id: 3, name: 'Book', price: 20, tags: ['education'] },
];
// --- Main Logic ---
const logger = new Logger(LogLevel.DEBUG);
logger.log('Application started', LogLevel.INFO);
const activeUsers = filterActiveUsers(users);
logger.log(`Active users: ${activeUsers.map(u => u.name).join(', ')}`);
const total = calculateTotal(products);
logger.log(`Total price: $${total}`);
const alice = getUserById(users, 1);
if (alice) {
logger.log(`Found user: ${alice.name}`);
}
const newUser = addRoleToUser(users[1], 'editor');
logger.log(`Updated user roles: ${newUser.roles.join(', ')}`);
const idVal = identity<string>('test');
logger.log(`Identity function returned: ${idVal}`);
const mapped = mapArray<number, string>([1, 2, 3], n => `Number: ${n}`);
logger.log(`Mapped array: ${mapped.join('; ')}`);
// --- File Operations (Mocked) ---
function saveDataToFile(filename: string, data: string) {
// Simulate file save
logger.log(`Data would be saved to ${filename}`);
}
saveDataToFile('output.txt', JSON.stringify(users));
// Update marker 4
// --- More Example Code ---
for (let i = 0; i < 10; i++) {
logger.log(`Loop iteration: ${i}`);
}
function* idGenerator() {
let id = 0;
while (true) {
yield id++;
}
}
const gen = idGenerator();
for (let i = 0; i < 5; i++) {
logger.log(`Generated id: ${gen.next().value}`);
}
class Calculator {
add(a: number, b: number): number {
return a + b;
}
multiply(a: number, b: number): number {
return a * b;
}
}
const calc = new Calculator();
logger.log(`Calc add: ${calc.add(2, 3)}`);
logger.log(`Calc multiply: ${calc.multiply(4, 5)}`);
// --- End of File ---
// Update marker 5
})();
