How to define the type for the value of an object property

Question

In TypeScript I can declare a typed Array as follows:

interface Something {
  a: number,
  b: number
}

const arr: Array<Something> = [{a:1, b:2}, {a:3, b:4}]

But how would I declare the type for the object equivalent:

const obj = {
  propA: {a:1, b:2},
  propB: {a:3, b:4}
}

Here, I don't care about the names of propA, propB, etc and I don't want an interface that defines the names of the top level properties but I do want to enforce that each property value is of type Something. Is this possible? Thanks in advance.

Answer 1

You can use { [key: string]: Something }:

const obj: { [key: string]: Something } = {
  propA: {a:1, b:2},
  propB: {a:3, b:4}
}

playground.