From b5e99a235425ea81bc075427f100dfe7b6b9ad91 Mon Sep 17 00:00:00 2001
From: Jean-Yves Moyen <jym@siteimprove.com>
Date: Wed, 25 Oct 2023 09:37:01 +0200
Subject: [PATCH] =?UTF-8?q?Properly=20use=20`Value.HasCalculation`=20in=20?=
 =?UTF-8?q?CSS=E2=80=AFvalues=20(#1491)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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* Proprely use Value.HasCalculation

* Add changeset
---
 .changeset/thin-melons-hope.md                |  5 +++
 .../alfa-css/src/value/collection/list.ts     | 44 ++++++++-----------
 .../alfa-css/src/value/collection/tuple.ts    | 29 +++++-------
 packages/alfa-css/src/value/resolvable.ts     |  2 +-
 packages/alfa-css/src/value/shadow.ts         | 35 ++++++---------
 5 files changed, 49 insertions(+), 66 deletions(-)
 create mode 100644 .changeset/thin-melons-hope.md

diff --git a/.changeset/thin-melons-hope.md b/.changeset/thin-melons-hope.md
new file mode 100644
index 0000000000..bf9fd45a48
--- /dev/null
+++ b/.changeset/thin-melons-hope.md
@@ -0,0 +1,5 @@
+---
+"@siteimprove/alfa-css": minor
+---
+
+**Breaking:** CSS `Value` types no longer accept a `CALC` parameter; it is automatically inferred
diff --git a/packages/alfa-css/src/value/collection/list.ts b/packages/alfa-css/src/value/collection/list.ts
index 9106dc08d1..44bb19cb0d 100644
--- a/packages/alfa-css/src/value/collection/list.ts
+++ b/packages/alfa-css/src/value/collection/list.ts
@@ -14,25 +14,24 @@ const { delimited, option, map, separatedList } = Parser;
 /**
  * @public
  */
-export class List<V extends Value, CALC extends boolean = boolean>
-  extends Value<"list", CALC>
+export class List<V extends Value>
+  extends Value<"list", Value.HasCalculation<[V]>>
   implements
     Iterable<V>,
-    Resolvable<List<Resolvable.Resolved<V>, false>, Resolvable.Resolver<V>>
+    Resolvable<List<Resolvable.Resolved<V>>, Resolvable.Resolver<V>>
 {
   public static of<V extends Value>(
     values: Iterable<V>,
-    separator = " "
-  ): List<V, Value.HasCalculation<[V]>> {
-    const array = Array.from(values);
-    return new List(array, separator, Value.hasCalculation(...array));
+    separator = " ",
+  ): List<V> {
+    return new List(Array.from(values), separator);
   }
 
   private readonly _values: Array<V>;
   private readonly _separator: string;
 
-  private constructor(values: Array<V>, separator: string, calculation: CALC) {
-    super("list", calculation);
+  private constructor(values: Array<V>, separator: string) {
+    super("list", Value.hasCalculation(...values));
     this._values = values;
     this._separator = separator;
   }
@@ -42,22 +41,15 @@ export class List<V extends Value, CALC extends boolean = boolean>
   }
 
   public resolve(
-    resolver?: Resolvable.Resolver<V>
-  ): List<Resolvable.Resolved<V>, false> {
+    resolver?: Resolvable.Resolver<V>,
+  ): List<Resolvable.Resolved<V>> {
     return this.map(
-      (value) => value.resolve(resolver) as Resolvable.Resolved<V>
+      (value) => value.resolve(resolver) as Resolvable.Resolved<V>,
     );
   }
 
-  public map<U extends Value>(
-    mapper: Mapper<V, U>
-  ): List<U, U extends Value<string, false> ? false : true> {
-    const array = this._values.map(mapper);
-    const calculation = array.some((value) =>
-      value.hasCalculation()
-    ) as U extends Value<string, false> ? false : true;
-
-    return new List(array, this._separator, calculation);
+  public map<U extends Value>(mapper: Mapper<V, U>): List<U> {
+    return new List(this._values.map(mapper), this._separator);
   }
 
   public equals<T extends Value>(value: List<T>): boolean;
@@ -88,7 +80,7 @@ export class List<V extends Value, CALC extends boolean = boolean>
     return {
       ...super.toJSON(),
       values: this._values.map(
-        (value) => value.toJSON() as Serializable.ToJSON<V>
+        (value) => value.toJSON() as Serializable.ToJSON<V>,
       ),
       separator: this._separator,
     };
@@ -121,11 +113,11 @@ export namespace List {
     separator: string,
     parseSeparator: CSSParser<any>,
     lower: number,
-    upper: number
+    upper: number,
   ): CSSParser<List<V>> {
     return map(
       separatedList(parseValue, parseSeparator, lower, upper),
-      (values) => List.of(values, separator)
+      (values) => List.of(values, separator),
     );
   }
 
@@ -136,12 +128,12 @@ export namespace List {
   export const parseCommaSeparated = <V extends Value>(
     parseValue: CSSParser<V>,
     lower: number = 1,
-    upper: number = Infinity
+    upper: number = Infinity,
   ) => parse(parseValue, ", ", parseComma, lower, upper);
 
   export const parseSpaceSeparated = <V extends Value>(
     parseValue: CSSParser<V>,
     lower: number = 1,
-    upper: number = Infinity
+    upper: number = Infinity,
   ) => parse(parseValue, " ", parseSpace, lower, upper);
 }
diff --git a/packages/alfa-css/src/value/collection/tuple.ts b/packages/alfa-css/src/value/collection/tuple.ts
index 99211ad66a..05bf231cb8 100644
--- a/packages/alfa-css/src/value/collection/tuple.ts
+++ b/packages/alfa-css/src/value/collection/tuple.ts
@@ -7,20 +7,18 @@ import { Value } from "../value";
 /**
  * @public
  */
-export class Tuple<T extends Array<Value>, CALC extends boolean = boolean>
-  extends Value<"tuple", CALC>
-  implements Resolvable<Tuple<Tuple.Resolved<T>, false>, Tuple.Resolver<T>>
+export class Tuple<T extends Array<Value>>
+  extends Value<"tuple", Value.HasCalculation<T>>
+  implements Resolvable<Tuple<Tuple.Resolved<T>>, Tuple.Resolver<T>>
 {
-  public static of<T extends Array<Value>>(
-    ...values: Readonly<T>
-  ): Tuple<T, Value.HasCalculation<T>> {
-    return new Tuple(values, Value.hasCalculation(...values));
+  public static of<T extends Array<Value>>(...values: Readonly<T>): Tuple<T> {
+    return new Tuple(values);
   }
 
   private readonly _values: Readonly<T>;
 
-  private constructor(values: Readonly<T>, calculation: CALC) {
-    super("tuple", calculation);
+  private constructor(values: Readonly<T>) {
+    super("tuple", Value.hasCalculation(...values));
     this._values = values;
   }
 
@@ -28,12 +26,9 @@ export class Tuple<T extends Array<Value>, CALC extends boolean = boolean>
     return this._values;
   }
 
-  public resolve(
-    resolver?: Tuple.Resolver<T>
-  ): Tuple<Tuple.Resolved<T>, false> {
-    return new Tuple<Tuple.Resolved<T>, false>(
+  public resolve(resolver?: Tuple.Resolver<T>): Tuple<Tuple.Resolved<T>> {
+    return new Tuple<Tuple.Resolved<T>>(
       this._values.map((value) => value.resolve(resolver)) as Tuple.Resolved<T>,
-      false
     );
   }
 
@@ -61,7 +56,7 @@ export class Tuple<T extends Array<Value>, CALC extends boolean = boolean>
     return {
       ...super.toJSON(),
       values: this._values.map((value) =>
-        value.toJSON()
+        value.toJSON(),
       ) as Serializable.ToJSON<T>,
     };
   }
@@ -80,7 +75,7 @@ export namespace Tuple {
   }
 
   export function isTuple<T extends Array<Value>>(
-    value: unknown
+    value: unknown,
   ): value is Tuple<T> {
     return value instanceof Tuple;
   }
@@ -94,7 +89,7 @@ export namespace Tuple {
    */
   export type Resolved<T extends Array<Value>> = T extends [
     infer Head extends Value,
-    ...infer Tail extends Array<Value>
+    ...infer Tail extends Array<Value>,
   ]
     ? [Resolvable.Resolved<Head>, ...Resolved<Tail>]
     : [];
diff --git a/packages/alfa-css/src/value/resolvable.ts b/packages/alfa-css/src/value/resolvable.ts
index f07bf4a70e..862ba471f7 100644
--- a/packages/alfa-css/src/value/resolvable.ts
+++ b/packages/alfa-css/src/value/resolvable.ts
@@ -16,7 +16,7 @@ export namespace Resolvable {
    */
   export type Resolved<V extends Value> = V extends Resolvable<infer U, unknown>
     ? U
-    : V;
+    : never;
 
   /**
    * @privateRemarks
diff --git a/packages/alfa-css/src/value/shadow.ts b/packages/alfa-css/src/value/shadow.ts
index d0cfbeabcb..f11155be83 100644
--- a/packages/alfa-css/src/value/shadow.ts
+++ b/packages/alfa-css/src/value/shadow.ts
@@ -21,9 +21,8 @@ export class Shadow<
     B extends Length = Length,
     S extends Length = Length,
     C extends Color = Color,
-    CALC extends boolean = boolean
   >
-  extends Value<"shadow", CALC>
+  extends Value<"shadow", Value.HasCalculation<[H, V, B, S, C]>>
   implements Resolvable<Shadow.Canonical, Shadow.Resolver>
 {
   public static of<
@@ -31,24 +30,16 @@ export class Shadow<
     V extends Length = H,
     B extends Length = Length,
     S extends Length = Length,
-    C extends Color = Color
+    C extends Color = Color,
   >(
     horizontal: H,
     vertical: V,
     blur: B,
     spread: S,
     color: C,
-    isInset: boolean
-  ): Shadow<H, V, B, S, C, Value.HasCalculation<[H, V, B, S]>> {
-    return new Shadow(
-      horizontal,
-      vertical,
-      blur,
-      spread,
-      color,
-      isInset,
-      Value.hasCalculation(horizontal, vertical, blur, spread)
-    );
+    isInset: boolean,
+  ): Shadow<H, V, B, S, C> {
+    return new Shadow(horizontal, vertical, blur, spread, color, isInset);
   }
 
   private readonly _horizontal: H;
@@ -65,9 +56,11 @@ export class Shadow<
     spread: S,
     color: C,
     isInset: boolean,
-    hasCalculation: CALC
   ) {
-    super("shadow", hasCalculation);
+    super(
+      "shadow",
+      Value.hasCalculation(horizontal, vertical, blur, spread, color),
+    );
     this._horizontal = horizontal;
     this._vertical = vertical;
     this._blur = blur;
@@ -108,7 +101,6 @@ export class Shadow<
       this._spread.resolve(resolver),
       this._color.resolve(),
       this._isInset,
-      false
     );
   }
   public equals(value: unknown): value is this {
@@ -161,8 +153,7 @@ export namespace Shadow {
     Length.Canonical,
     Length.Canonical,
     Length.Canonical,
-    Color.Canonical,
-    false
+    Color.Canonical
   >;
   export interface JSON extends Value.JSON<"shadow"> {
     horizontal: Length.JSON;
@@ -188,7 +179,7 @@ export namespace Shadow {
     : [T, T, T, T];
 
   function checkLength<T, N extends 3 | 4>(
-    max: N
+    max: N,
   ): (array: Array<T>) => array is Sized<T, N> {
     return (array): array is Sized<T, N> =>
       array.length >= 2 && array.length <= max;
@@ -198,7 +189,7 @@ export namespace Shadow {
     return parseIf(
       checkLength<Length, N>(max),
       separatedList(Length.parse, Token.parseWhitespace),
-      () => `Shadows must have between 2 and ${max} lengths`
+      () => `Shadows must have between 2 and ${max} lengths`,
     );
   }
 
@@ -273,7 +264,7 @@ export namespace Shadow {
           blur ?? Length.of(0, "px"),
           spread ?? Length.of(0, "px"),
           color ?? Keyword.of("currentcolor"),
-          isInset ?? false
+          isInset ?? false,
         ),
       ]);
     };