From e08947657cca2b9b78d53f316e9a7da8af162beb Mon Sep 17 00:00:00 2001
From: Kevin COMBRIAT <kevin@sc0ville.com>
Date: Fri, 15 Jan 2021 12:08:54 +0900
Subject: [PATCH] refactor(validation): Use a slightly more explicit api
 surface to define validations without the need for explicit lists

---
 example/Validations.res       | 24 ++++++++++++------------
 src/Formidable.res            |  6 ++----
 src/FormidableValidations.res | 30 +++++++++++++++++-------------
 3 files changed, 31 insertions(+), 29 deletions(-)

diff --git a/example/Validations.res b/example/Validations.res
index 56b7a7a..ad05cab 100644
--- a/example/Validations.res
+++ b/example/Validations.res
@@ -4,33 +4,33 @@ module Label = {
   type t = [#required | #email | #equals]
 }
 
-let required = {
-  Description.names: list{#required},
-  validator: ({label, value}) =>
+let required = (
+  #name(#required),
+  ({Validator.Args.label: label, value}) =>
     switch value {
     | "" => #error(#error(("required", label)))
     | _ => #ok(value)
     },
-}
+)
 
 let emailRegEx = %re("/.+@.+/")
 
-let email = {
-  Description.names: list{#email},
-  validator: ({label, value}) =>
+let email = (
+  #name(#email),
+  ({Validator.Args.label: label, value}) =>
     if emailRegEx->Js.Re.test_(value) {
       #ok(value)
     } else {
       #error(#error(("email", label)))
     },
-}
+)
 
-let equals = lens => {
-  Description.names: list{#equals},
-  validator: ({label, value, values}) =>
+let equals = lens => (
+  #name(#equals),
+  ({Validator.Args.label: label, value, values}) =>
     if lens.Optic.Lens.get(values) == value {
       #ok(value)
     } else {
       #error(#error(("equals", label)))
     },
-}
+)
diff --git a/src/Formidable.res b/src/Formidable.res
index f200b75..418d756 100644
--- a/src/Formidable.res
+++ b/src/Formidable.res
@@ -316,16 +316,14 @@ module Make = (ValidationLabel: Type, Error: Type, Values: Values): (
 
       let validationNames =
         validations->Option.mapWithDefault([], validations =>
-          validations->ArrayExtra.flatMap(validation =>
-            validation->Validations.getNames->List.toArray
-          )
+          validations->ArrayExtra.flatMap(Validations.getNames)
         )
 
       let hasValidation = name => validationNames->Js.Array2.includes(name)
 
       let validate = React.useCallback1((validationContext, values) =>
         validations->Option.mapWithDefault(#valid, validations =>
-          switch validations->Array.keepMap(((strategy, {validator})) =>
+          switch validations->Array.keepMap(((strategy, (_, validator))) =>
             if Validations.shouldValidate(~context=validationContext, ~strategy) {
               switch validator({
                 Validations.Validator.Args.label: errorLabel->OptionExtra.or(label),
diff --git a/src/FormidableValidations.res b/src/FormidableValidations.res
index 506c53d..c6b82b2 100644
--- a/src/FormidableValidations.res
+++ b/src/FormidableValidations.res
@@ -27,10 +27,17 @@ module Validator = {
 }
 
 module Description = {
-  type t<'values, 'value, 'error, 'label> = {
-    names: list<'label>,
-    validator: Validator.t<'values, 'value, 'error>,
-  }
+  @ocaml.doc(`Only the first "kind" is meant to be used by an application.
+The second one is used only internally when composing validations`)
+  type kind<'label> = [#name('label) | #names(array<'label>)]
+
+  let resolveKind = (kind: kind<'label>) =>
+    switch kind {
+    | #name(label) => [label]
+    | #names(labels) => labels
+    }
+
+  type t<'values, 'value, 'error, 'label> = (kind<'label>, Validator.t<'values, 'value, 'error>)
 }
 
 type t<'values, 'value, 'error, 'label> = (
@@ -38,23 +45,20 @@ type t<'values, 'value, 'error, 'label> = (
   Description.t<'values, 'value, 'error, 'label>,
 )
 
-let compose = (
-  {Description.names: names, validator},
-  {Description.names: names', validator: validator'},
-) => {
-  Description.names: names->List.concat(names'),
-  validator: field =>
+let compose = ((names, validator), (names', validator')) => (
+  names->Description.resolveKind->Js.Array2.concat(names'->Description.resolveKind)->#names,
+  field =>
     switch validator(field) {
     | #ok(_) => validator'(field)
     | #error(_) as error => error
     },
-}
+)
 
 let getStrategy = ((strategy, _)) => strategy
 
-let getNames = ((_, {Description.names: names})) => names
+let getNames = ((_, (names, _))) => names->Description.resolveKind
 
-let getValidator = ((_, {Description.validator: validator})) => validator
+let getValidator = ((_, (_, validator))) => validator
 
 @ocaml.doc(`Returns true if a validation should be performed in the given context.
 If no context is provided, always returns true`)