---
title: "How To Use Record Type In Typescript"
date: "2023-08-11"
slug: "how-to-use-record-type-in-typescript"
author: "Dany Paredes"
canonical: "https://danywalls.com/how-to-use-record-type-in-typescript"
description: "Today I was facing a problem where I wanted an object with a list of properties but with specific values like: For example: export type NBATeam = \"Lakers\" | \"Celtics\" | \"Bulls\" | \"Warriors\";\nconst nbaChampionships = { Lakers: 17, Celtics: 17..."
---

Today I was facing a problem where I wanted an object with a list of properties but with specific values like:

For example:

```typescript
export type NBATeam = "Lakers" | "Celtics" | "Bulls" | "Warriors";

const nbaChampionships = {
    Lakers: 17,
    Celtics: 17,
    Bulls: 6,
    Warriors: 6
};
```

How can Typescript help me to do it?

Well, TypeScript provides a list of utility types that make it easier to handle various type-related operations; one of these [utility types](https://www.typescriptlang.org/docs/handbook/utility-types.html) is the `Record` Type.

### **What is the** `Record` Type?

The `Record` type allows us to construct an object type with specified keys and their corresponding values, so we can think of it as defining a map or a dictionary.

In deep is like:

```typescript
type Record<K extends keyof any, T> = {
    [P in K]: T;
};
```

With `Record`, you're essentially telling TypeScript: "Hey, I want an object that has keys of type `K`, and every value under those keys should be of type `T`."

> Learn more about [Record Types](https://www.typescriptlang.org/docs/handbook/utility-types.html#recordkeys-type)

### **Example**

Suppose we want to create a type representing the number of championships won by different NBA teams. We can define our team names and the corresponding type for the number of championships:

```typescript
type NBATeam = "Lakers" | "Celtics" | "Bulls" | "Warriors";
type Championships = number;
```

Using the `Record` type, we can create a type that maps each NBA team to the number of championships they have won:

```typescript
type ChampionshipRecord = Record<NBATeam, Championships>;
```

This tells TypeScript that our `ChampionshipRecord` type is an object where every key is an `NBATeam`, and every value is a `Championships` (number).

Now, let's use this type:

```typescript
const nbaChampionships: ChampionshipRecord = {
    Lakers: 17,
    Celtics: 17,
    Bulls: 6,
    Warriors: 6
};

console.log(`Lakers have won ${nbaChampionships.Lakers} championships.`);
```

If you accidentally add a team that's not in our NBATeam type or provide a value for championships that isn't a number, it generates a compile-time error, ensuring our data stays consistent.

### **Recap**

For me `Record` is so powerful and helps to be it ensures objects conform to a specific shape. It guarantees that the keys and values of an object are of a certain type, adding a level of predictability to our codebase.

I hope it helps you ;)