purescript-bonjiri

An implementation for working with JS Promises via specifications. For when you want to make use of existing mechanisms in JS libs and debugging tools.

Bonjiri is basically chicken butt.

Usage

see Tests.

foreign import thunkPromise :: Unit -> B.JSPromise Int

main :: Effect Unit
main = do
  -- create a spec from a promise thunk
  let spec1 = B.fromThunk thunkPromise

  B.run
    do \_ -> fail "Spec should not fail"
    do \actual -> Assert.assertEqual { actual, expected: 1 }
    spec1

  -- just map on the value inside
  let spec2 = B.map (add 1) spec1

  B.run
    do \_ -> fail "Spec should not fail"
    do \actual -> Assert.assertEqual { actual, expected: 2 }
    spec2

  -- now throw an error from inside
  let spec3 = B.chain (\_ -> B.reject (unsafeToForeign "error")) spec2

  B.run
    do
      \f ->
        case runExcept (readString f) of
          Right actual -> Assert.assertEqual { actual, expected: "error" }
          Left _ -> fail "Could not decode error correctly"
    do \_ -> fail "Spec should fail"
    spec3

  -- catch the error and resolve a new value
  let spec4 = B.catch (\_ -> B.resolve "hi") spec3

  B.run
    do \_ -> fail "Spec should not fail"
    do \actual -> Assert.assertEqual { actual, expected: "hi" }
    spec4

  -- all
  let spec5 = B.all [spec1, spec1, spec1, spec1]

  B.run
    do \_ -> fail "Spec should not fail"
    do \actual -> Assert.assertEqual { actual, expected: [1, 1, 1, 1] }
    spec5

  -- apply
  let spec6 = B.apply (B.pure (add 1)) spec1

  B.run
    do \_ -> fail "Spec should not fail"
    do \actual -> Assert.assertEqual { actual, expected: 2 }
    spec6

  -- instances
  let spec7 = add <$> spec1 <*> spec1

  B.run
    do \_ -> fail "Spec should not fail"
    do \actual -> Assert.assertEqual { actual, expected: 2 }
    spec7

FAQ

Why are there instances?

Convenience. These may not work correctly.