What is the Record utility type? | TypeScript Interview Questions

What You'll Learn

Record<K, V> utility
Common use cases
Comparison with index signatures

Record<K, V>

Creates an object type with keys of type K and values of type V.

code.tsTypeScript

// Simple record
type Scores = Record<string, number>;

const scores: Scores = {
  alice: 95,
  bob: 87,
  charlie: 92
};

With Union Types

code.tsTypeScript

type Status = "pending" | "approved" | "rejected";

type StatusColors = Record<Status, string>;

const colors: StatusColors = {
  pending: "yellow",
  approved: "green",
  rejected: "red"
};

Complex Values

code.tsTypeScript

interface User {
  name: string;
  email: string;
}

type UserMap = Record<string, User>;

const users: UserMap = {
  u1: { name: "John", email: "john@example.com" },
  u2: { name: "Jane", email: "jane@example.com" }
};

Record vs Index Signature

code.tsTypeScript

// Index signature
interface Obj1 {
  [key: string]: number;
}

// Record (equivalent)
type Obj2 = Record<string, number>;

// Record is more concise and works with union keys