purescript-jajanmen

Cool type-safe Symbol query parameterized helper for Node-SQLite3.

Because jajanmen is delicious, and my other library is called Chanpon.

See the post about this library here: https://github.com/justinwoo/my-blog-posts#well-typed-parameterized-sqlite-parameters-with-purescript

See the talk about this library here: https://speakerdeck.com/justinwoo/superior-string-spaghetti-with-purescript-jajanmen

Usage

First, prepare some queries:

-- inferred type:
getEm
  :: forall a b
   . J.AllowedParamType a
  => J.AllowedParamType b
  => SL.DBConnection
  -> { "$name" :: a, "$count" :: b }
  -> Aff Foreign
getEm db = J.queryDB db queryP
  where
    queryP = SProxy :: SProxy "select name, count from mytable where name = $name and count = $count"

-- inferred type:
getSomethin :: SL.DBConnection -> Aff Foreign
getSomethin db = J.queryDB db queryP params
  where
    queryP = SProxy :: SProxy "select name, count from mytable where name = $name and count = $count"
    params = { "$name": "asdf", "$count": 4 }

-- inferred type:
addSomethin
  :: forall a b
   . J.AllowedParamType a
  => J.AllowedParamType b
  => SL.DBConnection
  -> { "$name" :: a, "$count" :: b }
  -> Aff Foreign
addSomethin db params = J.queryDB db queryP params
  where
    queryP = SProxy :: SProxy "insert or replace into mytable (name, count) values ($name, $count)"

Then put it to work:

type MyRow = { name :: String, count :: Int }

main :: Effect Unit
main = launchAff_ do
  db <- SL.newDB "./test/testdb.sqlite"
  _ <- SL.queryDB db "create table if not exists mytable (name text, count int)" []
  _ <- SL.queryDB db "delete from mytable" []
  _ <- addSomethin db { "$name": "apples", "$count": 3 }
  _ <- addSomethin db { "$name": "asdf", "$count": 4 }

  f1 <- getEm db { "$name": "apples", "$count": 3 }
  testResult f1 [{ name: "apples", count: 3 }]

  f2 <- getSomethin db
  testResult f2 [{ name: "asdf", count: 4 }]

  log "tests passed"
  where
    testResult f expected =
      case JSON.read f of
        Left e -> throwError (error $ show e)
        Right (actual :: Array MyRow) -> assertEqual { actual, expected }
    assertEqual = liftEffect <<< Assert.assertEqual