Type assertions for items in an array

type-assertions-array.ts

const list = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16] as const;

type List = typeof list;

type CheckListItems<Items extends readonly number[]> = Items extends readonly [
  infer First,
  ...infer Rest,
]
  ? First extends 3
    ? 'fail'
    : Rest extends readonly number[]
      ? CheckListItems<Rest>
      : never
  : 'pass';

type Result = CheckListItems<List>;

// eslint-disable-next-line @typescript-eslint/no-unused-vars
const assertPass = <T extends 'pass'>() => null;

assertPass<CheckListItems<List>>();