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Advanced Types: Literal, Tuple, and More

Intermediate
100 XP
40 min
Lesson Content

Advanced Types in TypeScript

TypeScript offers powerful type features that make your code more precise and type-safe.

Literal Types

// Specific string values
let status: "pending" | "approved" | "rejected";

// Specific number values
let dice: 1 | 2 | 3 | 4 | 5 | 6;

Tuple Types

// Fixed-length array with specific types
let coordinates: [number, number] = [10, 20];
let person: [string, number, boolean] = ["John", 30, true];

Type Aliases

type ID = string | number;
type Status = "active" | "inactive";

type User = {
  id: ID;
  status: Status;
};
Example Code

Use literal types and tuples

type Status = "loading" | "success" | "error";

function handleStatus(status: Status): string {
  return `Status: ${status}`;
}

let point: [number, number] = [10, 20];
console.log(`Point: (${point[0]}, ${point[1]})`);
console.log(handleStatus("success"));

Expected Output:

Point: (10, 20)
Status: success
Study Tips
  • •Read the theory content thoroughly before practicing
  • •Review the example code to understand key concepts
  • •Proceed to the Practice tab when you're ready to code