I was using TypeScript in Deno to build a sample project and I had to destructure an object. I am familiar with TypeScript basics but sometimes I hit a problem.

Object destructuring was one of those.

I wanted to do

const { name, age } = body.value

I tried adding the string and number types like this:

const { name: string, age: number } = body.value

But this didn’t work. It apparently worked, but in reality this is assigning the name property to the string variable, and the age property value to the number variable.

The correct syntax is this:

const { name, age }: { name: string; age: number } = body.value

The best way to approach this would be to create a type or interface for that data:

interface Dog {
  name: string
  age: number
}

Then you can write the above in this way, which is shorter:

const dog: Dog = body.value

Lessons in this unit:

0:	Introduction
1:	Your first TypeScript program
2:	Types
3:	Typing functions
4:	The editor helps you with type errors
5:	Running TypeScript code
6:	Valid types
7:	Type aliases and interfaces
8:	Union types
9:	Typing arrays with generics
10:	The DX of editing TypeScript
11:	There's more...
12:	TypeScript declare a type that can be a string or array of strings
13:	TypeScript, disable checks for `declared but its value is never read`
14:	▶︎ Object destructuring with types in TypeScript
15:	TypeScript Tutorial
16:	Zod: Type-Safe Schema Validation for TypeScript
17:	How I fixed some trouble importing types in .d.ts files