5dab988 · rowtype-yoga/purescript-yoga-http-api

git.iko.soy/rowtype-yoga/purescript-yoga-http-api

on feat/custom-type-errors help sign in

feat: Add custom type error for invalid response record structure

Add a helpful compile-time error message when users provide response records with invalid fields (e.g., including 'status' or 'statusCode' fields). The error message clearly explains: - Valid response record structure (body required, headers optional) - Examples of correct usage - Common mistakes to avoid This improves developer experience by catching structural errors at compile time with actionable feedback instead of generic type mismatch errors.

commit5dab98820b265e2c6bcc54eae3ff2d836e0f8865 authorMark <mark.eibes@gmail.com> dateFri 6 Feb 2026, 21:53 (8 months ago) parentcb61c73

3 files changed+41−1

compare with feat/custom-type-errors

unifiedsplit

src/Yoga/HTTP/API/Path.purs+1−1 src/Yoga/HTTP/API/Route/Response.purs+38 src/Yoga/HTTP/API/Route/StatusCode.purs+2

src/Yoga/HTTP/API/Path.purs+1−1

@@ -34,7 +34,6 @@ import Prim.Row as Row

3434import Record as Record

3535import Type.Proxy (Proxy(..))

3636import Unsafe.Coerce (unsafeCoerce)

37−

3837--------------------------------------------------------------------------------

3938-- Type-Level Path DSL

4039--------------------------------------------------------------------------------

@@ -242,6 +241,7 @@ instance parseParamNumber :: ParseParam Number where

242241 Nothing -> Left $ "Expected a number but got: " <> s

243242 Just n -> Right (Int.toNumber n) -- Simple version, doesn't handle floats

244243

244+

245245-- | Parse a URL string into a record of typed path parameters

246246-- |

247247-- | Examples:

src/Yoga/HTTP/API/Route/Response.purs+38

@@ -19,6 +19,7 @@ import Data.Variant (Variant)

1919import Data.Variant as Variant

2020import Prim.Row (class Cons)

2121import Prim.RowList as RL

22+import Prim.TypeError (class Fail, Text, Above)

2223import Type.Proxy (Proxy(..))

2324import Unsafe.Coerce (unsafeCoerce)

2425

@@ -70,6 +71,43 @@ instance toResponseRLBodyHeaders ::

7071else instance toResponseRLBodyOnly ::

7172 ToResponseRL (RL.Cons "body" body RL.Nil) () body

7273

74+-- Invalid record structure: has fields other than "body" and "headers"

75+else instance toResponseRLInvalid ::

76+ ( Fail

77+ ( Above

78+ (Text "Invalid response record structure.")

79+ ( Above

80+ (Text "")

81+ ( Above

82+ (Text "Response records must contain ONLY:")

83+ ( Above

84+ (Text " • body :: YourBodyType (required)")

85+ ( Above

86+ (Text " • headers :: Record (...) (optional)")

87+ ( Above

88+ (Text "")

89+ ( Above

90+ (Text "Valid examples:")

91+ ( Above

92+ (Text " { body: user }")

93+ ( Above

94+ (Text " { body: user, headers: { \"Location\": \"/users/123\" } }")

95+ ( Above

96+ (Text "")

97+ (Text "Do not include 'status', 'statusCode', or other fields.")

98+ )

99+ )

100+ )

101+ )

102+ )

103+ )

104+ )

105+ )

106+ )

107+ )

108+ ) =>

109+ ToResponseRL rl headers body

110+

73111--------------------------------------------------------------------------------

74112-- Response Construction Helpers

75113--------------------------------------------------------------------------------

src/Yoga/HTTP/API/Route/StatusCode.purs+2

@@ -9,6 +9,7 @@ import Prelude

1010import Type.Proxy (Proxy(..))

1111import Data.Newtype (class Newtype)

12+import Prim.TypeError (class Fail, Text, Beside, Above, Quote)

1213

1314newtype StatusCode = StatusCode Int

1415

@@ -225,6 +226,7 @@ instance StatusCodeMap "notExtended" where

225226instance StatusCodeMap "networkAuthenticationRequired" where

226227 statusCodeFor _ = StatusCode 511

227228

229+

228230--------------------------------------------------------------------------------

229231-- Helper Functions

230232--------------------------------------------------------------------------------