Function transfer

packages/effect/test/STM.test.ts:103–115

(
  receiver: TRef.TRef<number>,
  sender: TRef.TRef<number>,
  much: number
)

  )

const transfer = (
  receiver: TRef.TRef<number>,
  sender: TRef.TRef<number>,
  much: number
): Effect.Effect<number> =>
  pipe(
    TRef.get(sender),
    STM.tap((balance) => STM.check(() => balance >= much)),
    STM.tap(() => pipe(receiver, TRef.update((n) => n + much))),
    STM.tap(() => pipe(sender, TRef.update((n) => n - much))),
    STM.zipRight(TRef.get(receiver)),
    STM.commit
  )

const compute3TRefN = (
  n: number,