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Utility Types Development Tutorials, Guides & Insights

Unlock 2+ expert-curated utility types tutorials, real-world code snippets, and modern dev strategies. From fundamentals to advanced topics, boost your utility types skills on DeveloperBreeze.

Cheatsheet
typescript

TypeScript Generics and Advanced Types Cheatsheet: Master Complex Type Systems 

function getProperty<T, K extends keyof T>(obj: T, key: K) {
  return obj[key];
}

const person = { name: 'Alice', age: 25 };
const name = getProperty(person, 'name'); // Works
// const invalid = getProperty(person, 'invalidKey'); // Error: Argument of type '"invalidKey"' is not assignable to parameter of type '"name" | "age"'.

Here, K is constrained to the keys of the object T, ensuring that only valid property names can be used.

Aug 20, 2024
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Tutorial
typescript

Advanced TypeScript: Type Inference and Advanced Types 

function getProperty<T, K extends keyof T>(obj: T, key: K): T[K] {
  return obj[key];
}

const person = { name: 'Alice', age: 30 };

const name = getProperty(person, 'name'); // valid
const age = getProperty(person, 'age');   // valid
// const gender = getProperty(person, 'gender'); // error
interface ApiResponse<T = any> {
  data: T;
  status: number;
  error?: string;
}

const response: ApiResponse<{ userId: number }> = {
  data: { userId: 1 },
  status: 200
};

const defaultResponse: ApiResponse = {
  data: {},
  status: 200
};

Aug 05, 2024
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