@effect-ts/system/_src/Testing/Int/index.ts

Effect-TS is a zero dependency set of libraries to write highly productive, purely functional TypeScript at scale.

// ets_tracing: off

export interface IntBrand {
  readonly IntBrand: unique symbol
}

export type Int = number & IntBrand

export function Int(n: number): Int {
  if (!Number.isInteger(n)) {
    throw new Error("not an integer")
  }
  return n as Int
}