testEpic.js

async function retry(foo, count = 1, delay) {
  let error;
  while (count--) {
    try {
      return foo()
    } catch (e) {
      error = e
      await timeout(delay)
    }
  }
  throw error
}

async function testEpic() {
  try {
    const foo = () => fetch('/1234')
    const data = retry(foo, 3, 3000)
    dispatch(data)
  } catch (e) {
    dispatch(e)
  }
}