How to use `some` to partially check items in object using TypeScript

I have an object:

interface MYInterface {
  aaa: number;
  bbb: number;
  ccc?: number | undefined;

const myObject: MYInterface = {
  aaa: 0,
  bbb: 0,
  ccc: 132,

I want to check if some keys in this object, satisfy a condition! I'm using Array.some(...) like below:

const res = ['aaa', 'bbb'].some((key) => myObject[key] > 0)

but for myObject[key] I'm getting a TypeScript error about:

Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'INxStateCounts'.
  No index signature with a parameter of type 'string' was found on type 'INxStateCounts'.

I know that what am I trying to do is checking array of strings (keys) with objects but my array contains those keys in string.

I have tried to cast key as keyof MYInterface but no luck! I was getting so many other errors. How can I fix this?

Also my object is very big, here I use 3 properties to demonstrate the issue.

Just in case if you want to test.


  • Just make more concrete typing in your code, like this:

    function someOf<T>(keys: (keyof T)[], obj: T): boolean {
      return keys.some((key) => obj[key] > 0)
    const res = someOf(['aaa', 'bbb'], myObject);