TypeScript: production best practices

TypeScript is powerful — but only when used deliberately.

1. Strict typing

Avoid any. Use unknown for values with unknown shape:

Копировать
1// ❌ Bad
2function processData(data: any) {
3  return data.value;
4}
5
6// ✅ Good
7function processData(data: unknown) {
8  if (typeof data === 'object' && data !== null && 'value' in data) {
9    return (data as { value: string }).value;
10  }
11  throw new Error('Invalid data');
12}

2. Type utilities

Leverage built‑in helpers:

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1type User = {
2  id: string;
3  name: string;
4  email: string;
5  age?: number;
6};
7
8// Pick — select fields
9type UserPreview = Pick<User, 'id' | 'name'>;
10
11// Omit — remove fields
12type UserWithoutEmail = Omit<User, 'email'>;
13
14// Partial — all fields optional
15type PartialUser = Partial<User>;

3. Explicit return types

Always declare what a function returns:

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1// ✅ Good
2function getUser(id: string): Promise<User> {
3  return fetchUser(id);
4}

Takeaways

TypeScript helps write safer code but requires discipline. Follow these practices to keep your codebase clean and robust.