`promise` is undefined until first load/run

In Version 8 the run method no longer returns a promise. Instead the promise prop should be used. However, when using useFetch, the promise property is undefined. Here is a test that demonstrates this:

  test("defer=true allows using the promise", () => {
    let check = 0
    const component = (
      <Fetch input="/test" options={{ defer: true }}>
        {({ run, promise }) => (
          <button
            onClick={() => {
              run()
              promise
                .then(() => {
                  return (check = 1)
                })
                .catch(() => {})
            }}
          >
            run
          </button>
        )}
      </Fetch>
    )
    const { getByText } = render(component)
    fireEvent.click(getByText("run"))
    expect(check).toEqual(1)
  })

I’ll also add a Pull-Request with these failing tests.

[ghengeveld]

@bogdansoare I feel your pain. I’m actually inclined to restore the chainability of run by returning a Thenable (PromiseLike) from it. Because it’s not an actual Promise it avoids the uncaught exception issue (although await will still throw on rejection because it treats the Thenable as a Promise). However I think we should be careful not to regress in previously resolved problems. It’s clear that the promise prop is causing more harm than good.

[bogdansoare]

also having this issue, run should return a promise