Generate the browser contract from ProductApi

app/GenerateContract.hs

@@ -0,0 +1,19 @@
+module Main (main) where
+
+import qualified Data.ByteString.Lazy as BL
+import qualified Data.Text.IO as TIO
+import           Nuthatch.Http.Contract
+  ( renderContractFixtures
+  , renderTypeScriptContract
+  )
+import           System.Environment (getArgs)
+
+main :: IO ()
+main = do
+  arguments <- getArgs
+  case arguments of
+    [contractOutput, fixtureOutput] -> do
+      TIO.writeFile contractOutput renderTypeScriptContract
+      BL.writeFile fixtureOutput renderContractFixtures
+    _ -> fail
+      "usage: nuthatch-generate-web-contract CONTRACT_OUTPUT FIXTURE_OUTPUT"