feat: add array items validation

Author: mstream

Examples.generated.md

@@ -18,6 +18,7 @@ null
 #### Output
 ```
 ✓ no violations
+
 ```
 
 ### ► A boolean value against a schema accepting only null values
@@ -33,9 +34,12 @@ true
 ```
 #### Output
 ```
-✗ Invalid type. Expected null but got boolean.
-  Schema path: #/type
-  JSON path: $
+✗
+  Schema path:
+  #/type
+  JSON path:
+  $
+  Invalid type. Expected null but got boolean.
 ```
 
 ### ► A boolean value against a schema accepting only null and string values
@@ -51,8 +55,44 @@ true
 ```
 #### Output
 ```
-✗ Invalid type. Expected null or string but got boolean.
-  Schema path: #/type
-  JSON path: $
+✗
+  Schema path:
+  #/type
+  JSON path:
+  $
+  Invalid type. Expected null or string but got boolean.
+```
+
+### ► An array with 2 out of 5 items not matching the desired item type
+When schema requires items to conform to a certain schema, every single value in the array has to.
+#### Input
+##### JSON schema
+```json
+{"items":{"type":["null"]},"type":["array"]}
+```
+##### JSON
+```json
+[null,false,null,true,null]
+```
+#### Output
+```
+✗
+  Schema path:
+  #
+  JSON path:
+  $
+  Invalid array: 
+  -
+    Schema path:
+    #/items/type
+    JSON path:
+    $[1]
+    Invalid type. Expected null but got boolean.
+  -
+    Schema path:
+    #/items/type
+    JSON path:
+    $[3]
+    Invalid type. Expected null but got boolean.
 ```
 

src/purs/JsonSchema/JsonPath.purs

@@ -0,0 +1,36 @@
+module JsonSchema.JsonPath
+  ( JsonPath
+  , JsonPathSegment(..)
+  , render
+  ) where
+
+import Prelude
+
+import Data.Foldable (foldMap)
+import Data.Generic.Rep (class Generic)
+import Data.List (List)
+import Data.List as List
+import Data.Show.Generic (genericShow)
+
+type JsonPath = List JsonPathSegment
+
+render ∷ JsonPath → String
+render = ("$" <> _) <<< foldMap f <<< List.reverse
+  where
+  f ∷ JsonPathSegment → String
+  f = case _ of
+    ItemIndex idx →
+      "[" <> show idx <> "]"
+    Property name →
+      "/" <> name
+
+data JsonPathSegment
+  = ItemIndex Int
+  | Property String
+
+derive instance Eq JsonPathSegment
+derive instance Generic JsonPathSegment _
+derive instance Ord JsonPathSegment
+
+instance Show JsonPathSegment where
+  show = genericShow

src/purs/JsonSchema/SchemaPath.purs

@@ -0,0 +1,34 @@
+module JsonSchema.SchemaPath
+  ( SchemaPath
+  , SchemaPathSegment(..)
+  , render
+  ) where
+
+import Prelude
+
+import Data.Foldable (foldMap)
+import Data.Generic.Rep (class Generic)
+import Data.List (List)
+import Data.List as List
+import Data.Show.Generic (genericShow)
+
+type SchemaPath = List SchemaPathSegment
+
+render ∷ SchemaPath → String
+render = ("#" <> _) <<< foldMap f <<< List.reverse
+  where
+  f ∷ SchemaPathSegment → String
+  f = case _ of
+    Items →
+      "/items"
+    TypeKeyword →
+      "/type"
+
+data SchemaPathSegment = Items | TypeKeyword
+
+derive instance Eq SchemaPathSegment
+derive instance Generic SchemaPathSegment _
+derive instance Ord SchemaPathSegment
+
+instance Show SchemaPathSegment where
+  show = genericShow