chore: enhance utility type

- Reduce code lines - extend basic types to advanced types - Offer custom types - Add a new type called `Discard`
halvaradop · Nov 29, 2024 · 59d6659 · 59d6659
1 parent 0585436
commit 59d6659
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diff --git a/src/array-types.ts b/src/array-types.ts
@@ -1,4 +1,3 @@
-import type { ToUnion } from "./object-types.js"
 import type { Equals } from "./test.js"
 
 /**
@@ -229,18 +228,21 @@ export type AllEquals<Array extends unknown[], Comparator> = Array extends [infe
 
 type ChunkImplementation<
     Array extends unknown[],
-    Size extends number,
+    Length extends number,
     Build extends unknown[] = [],
     Partition extends unknown[] = [],
 > = Array extends [infer Item, ...infer Spread]
-    ? [...Partition, Item]["length"] extends Size
-        ? ChunkImplementation<Spread, Size, [...Build, [...Partition, Item]], []>
-        : ChunkImplementation<Spread, Size, Build, [...Partition, Item]>
-    : Partition["length"] extends 0
+    ? [...Partition, Item]["length"] extends Length
+        ? ChunkImplementation<Spread, Length, [...Build, [...Partition, Item]], []>
+        : ChunkImplementation<Spread, Length, Build, [...Partition, Item]>
+    : Size<Partition> extends 0
       ? Build
       : [...Build, Partition]
 
-export type Chunk<Array extends unknown[], Size extends number> = ChunkImplementation<Array, Size, [], []>
+/**
+ * TODO: add examples
+ */
+export type Chunk<Array extends unknown[], Length extends number> = ChunkImplementation<Array, Length, [], []>
 
 type ZipImplementation<T, U, Build extends unknown[] = []> = T extends [infer ItemT, ...infer SpreadT]
     ? U extends [infer ItemU, ...infer SpreadU]
@@ -290,25 +292,18 @@ export type CompareArrayLength<T extends any[], U extends any[]> = T extends [an
     ? U extends [any, ...infer SpreadU]
         ? CompareArrayLength<SpreadT, SpreadU>
         : 1
-    : U extends [infer Item, ...infer Spread]
-      ? -1
-      : 0
+    : Size<U> extends 0
+      ? 0
+      : -1
 
 type UniqueImplementation<Array extends unknown[], Uniques extends unknown = never, Set extends unknown[] = []> = Array extends [
     infer Item,
     ...infer Spread,
 ]
-    ? HasImplementation<Set, Item> extends true
+    ? Includes<Set, Item> extends true
         ? UniqueImplementation<Spread, Uniques, Set>
         : UniqueImplementation<Spread, Uniques | Item, [...Set, Item]>
     : Set
-
-type HasImplementation<Array extends unknown[], Compare extends unknown> = Array extends [infer Item, ...infer Spread]
-    ? Equals<Item, Compare> extends true
-        ? true
-        : HasImplementation<Spread, Compare>
-    : false
-
 /**
  * Returns the uniques values of an array
  *
@@ -320,3 +315,39 @@ type HasImplementation<Array extends unknown[], Compare extends unknown> = Array
  * type Uniques2 = Unique<["a", "b", "c", "a", "b"]>;
  */
 export type Unique<Array extends unknown[]> = UniqueImplementation<Array>
+
+/**
+ * Create an union type based in the literal values of the tuple provided.
+ * This utility type is similar to `TupleToUnion` but this utility type
+ * receive whatever type
+ *
+ * @example
+ * // Expected: 1
+ * type TupleNumber = ToUnion<1>;
+ *
+ * // Expected: "foo"
+ * type TupleString = ToUnion<"foo">;
+ *
+ * // Expected: 1 | ["foo" | "bar"]
+ * type TupleMultiple = ToUnion<1 | ["foo" | "bar"]>;
+ */
+export type ToUnion<T> = T extends [infer Item, ...infer Spread] ? Item | ToUnion<Spread> : T
+
+/**
+ * Check if a value exists within a tuple and is equal to a specific value
+ *
+ * @example
+ * // Expected: true
+ * type IncludesNumber = Includes<[1, 2, 3], 3>;
+ *
+ * // Expected: true
+ * type IncludesString = Includes<["foo", "bar", "foobar"], "bar">;
+ *
+ * // Expected: false
+ * type NoIncludes = Includes<["foo", "bar", "foofoo"], "foobar">;
+ */
+export type Includes<Array extends unknown[], Match> = Array extends [infer Compare, ...infer Spread]
+    ? Equals<Compare, Match> extends true
+        ? true
+        : Includes<Spread, Match>
+    : false
diff --git a/src/object-types.ts b/src/object-types.ts
@@ -1,4 +1,5 @@
 import type { Equals } from "./test.js"
+import type { IsNever } from "./type-guards.js"
 import type { ArgsFunction, ReturnTypeOf } from "./types.js"
 
 /**
@@ -35,11 +36,35 @@ export type DeepReadonly<Obj extends object> = {
 }
 
 /**
+ * TODO: add examples
+ *
  * Exclude properties of type `Match` from type `T`
  */
 export type Exclude<T, Match> = T extends Match ? never : T
 
 /**
+ * Compare two types and return `never` if the type `T` extends the type `Match`,
+ * otherwise return the type `T`.
+ *
+ * @example
+ * // Expected: number
+ * type A = Discard<string | number, string>;
+ * // Expected: string | number
+ * type B = Discard<string | number, boolean>;
+ */
+export type Discard<Compare, Match, Value = never, Reverse extends boolean = false> = Reverse extends true
+    ? Compare extends Match
+        ? Value
+        : never
+    : Compare extends Match
+      ? never
+      : IsNever<Value> extends true
+        ? Compare
+        : Value
+
+/**
+ * TODO: add examples
+ *
  * Get the type of the resolved value of a PromiseLike object.
  */
 export type Awaited<T extends PromiseLike<unknown>> =
@@ -79,25 +104,6 @@ export type Pick<Obj extends object, Keys extends keyof Obj> = {
     [Property in Keys]: Obj[Property]
 }
 
-/**
- * Check if a value exists within a tuple and is equal to a specific value
- *
- * @example
- * // Expected: true
- * type IncludesNumber = Includes<[1, 2, 3], 3>;
- *
- * // Expected: true
- * type IncludesString = Includes<["foo", "bar", "foobar"], "bar">;
- *
- * // Expected: false
- * type NoIncludes = Includes<["foo", "bar", "foofoo"], "foobar">;
- */
-export type Includes<Array extends unknown[], Match> = Array extends [infer Compare, ...infer Spread]
-    ? Equals<Compare, Match> extends true
-        ? true
-        : Includes<Spread, Match>
-    : false
-
 /**
  * Creates a new type that omits properties from an object type based on another type
  *
@@ -106,7 +112,7 @@ export type Includes<Array extends unknown[], Match> = Array extends [infer Comp
  * type NoEmailPerson = Omit<{ name: string; age: number; email: string }, "email">;
  */
 export type Omit<Obj extends object, Keys extends keyof Obj> = {
-    [Property in keyof Obj as Property extends Keys ? never : Property]: Obj[Property]
+    [Property in keyof Obj as Discard<Property, Keys>]: Obj[Property]
 }
 
 /**
@@ -124,7 +130,9 @@ export type Omit<Obj extends object, Keys extends keyof Obj> = {
  * // Expected: "foo" | "bar"
  * type PropsFooBar = Properties<Foo, Bar>;
  */
-export type Properties<Obj1 extends object, Obj2 extends object> = keyof Obj1 | keyof Obj2
+export type Properties<Obj1 extends object, Obj2 extends object, Extends extends boolean = false> = Extends extends true
+    ? keyof Obj1 & keyof Obj2
+    : keyof Obj1 | keyof Obj2
 
 /**
  * Creates a new object by merging two objects. Properties from `Obj1` override properties
@@ -148,6 +156,10 @@ export type Merge<Obj1 extends object, Obj2 extends object> = {
     [Property in Properties<Obj1, Obj2>]: RetrieveKeyValue<Obj2, Obj1, Property>
 }
 
+type IntersectionImplementation<Obj1 extends object, Obj2 extends object, Keys = Properties<Obj1, Obj2, true>> = {
+    [Property in Properties<Obj1, Obj2> as Discard<Property, Keys>]: RetrieveKeyValue<Obj1, Obj2, Property>
+}
+
 /**
  * Create a new object based in the difference keys between the objects.
  *
@@ -166,13 +178,7 @@ export type Merge<Obj1 extends object, Obj2 extends object> = {
  * // Expected: { gender: number }
  * type DiffFoo = Intersection<Foo, Bar>;
  */
-export type Intersection<Obj1 extends object, Obj2 extends object> = {
-    [Property in Properties<Obj1, Obj2> as Property extends keyof Obj1 & keyof Obj2 ? never : Property]: RetrieveKeyValue<
-        Obj1,
-        Obj2,
-        Property
-    >
-}
+export type Intersection<Obj1 extends object, Obj2 extends object> = IntersectionImplementation<Obj1, Obj2>
 
 /**
  * Create a new object based in the type of its keys
@@ -188,10 +194,12 @@ export type Intersection<Obj1 extends object, Obj2 extends object> = {
  * type UserStr = PickByType<User, string>;
  */
 export type PickByType<Obj extends object, Type> = {
-    [Property in keyof Obj as Obj[Property] extends Type ? Property : never]: Obj[Property]
+    [Property in keyof Obj as Discard<Obj[Property], Type, Property, true>]: Obj[Property]
 }
 
 /**
+ * TODO: add examples
+ *
  * Converts the specified keys of an object into optional ones
  *
  * @example
@@ -205,9 +213,7 @@ export type PickByType<Obj extends object, Type> = {
  * type UserPartialName = PartialByKeys<User, "name">;
  */
 export type PartialByKeys<Obj extends object, Keys extends keyof Obj = keyof Obj> = Prettify<
-    {
-        [Property in keyof Obj as Property extends Keys ? never : Property]: Obj[Property]
-    } & { [Property in Keys]?: Obj[Property] }
+    Partial<Pick<Obj, Keys>> & Omit<Obj, Keys>
 >
 
 /**
@@ -228,23 +234,29 @@ export type OmitByType<Obj extends object, Type> = {
 }
 
 /**
+ * TODO: add examples
+ *
  * Extracts the value of a key from an object and returns a new object with that value,
  * while keeping the other values unchanged.
  */
 export type FlattenProperties<Obj extends object, Keys extends keyof Obj> = Prettify<
     {
-        [Property in keyof Obj as Property extends Keys ? never : Property]: Obj[Property]
+        [Property in keyof Obj as Discard<Property, Keys>]: Obj[Property]
     } & Obj[Keys]
 >
 
 /**
+ * TODO: add examples
+ *
  * Removes the properties whose keys start with an underscore (_).
  */
 export type PublicOnly<Obj extends object> = {
-    [Property in keyof Obj as Property extends `_${string}` ? never : Property]: Obj[Property]
+    [Property in keyof Obj as Discard<Property, `_${string}`>]: Obj[Property]
 }
 
 /**
+ * TODO: add examples
+ *
  * Checks if a key exists in either of the two objects and returns its value.
  * If the key does not exist in either object, it returns `never`.
  */
@@ -269,11 +281,7 @@ export type RetrieveKeyValue<Obj1 extends object, Obj2 extends object, Key> = Ke
  * type UserRequiredName = RequiredByKeys<User, "name">;
  */
 export type RequiredByKeys<Obj extends object, Keys extends keyof Obj = keyof Obj> = Prettify<
-    {
-        [Property in keyof Obj as Property extends Keys ? never : Property]: Obj[Property]
-    } & {
-        [Property in keyof Obj as Property extends Keys ? Property : never]-?: Obj[Property]
-    }
+    Required<Pick<Obj, Keys>> & Omit<Obj, Keys>
 >
 
 /**
@@ -372,23 +380,6 @@ type MergeAllImplementation<Array extends readonly object[], Merge extends objec
  */
 export type MergeAll<Array extends readonly object[]> = MergeAllImplementation<Array, {}>
 
-/**
- * Create an union type based in the literal values of the tuple provided.
- * This utility type is similar to `TupleToUnion` but this utility type
- * receive whatever type
- *
- * @example
- * // Expected: 1
- * type TupleNumber = ToUnion<1>;
- *
- * // Expected: "foo"
- * type TupleString = ToUnion<"foo">;
- *
- * // Expected: 1 | ["foo" | "bar"]
- * type TupleMultiple = ToUnion<1 | ["foo" | "bar"]>;
- */
-export type ToUnion<T> = T extends [infer Item, ...infer Spread] ? Item | ToUnion<Spread> : T
-
 /**
  * Create a new object type appending a new property with its value
  *

diff --git a/src/string-mappers.ts b/src/string-mappers.ts
@@ -30,7 +30,8 @@ export type Trim<Str extends string> = Str extends `${WhiteSpaces}${infer Charac
       : Str
 
 /**
- *  Converts a string to uppercase
+ * TODO: add example
+ * Converts a string to uppercase
  */
 export type Uppercase<Str extends string> = Str extends `${infer Char}${infer Characters}`
     ? Char extends keyof LetterToUppercase
@@ -39,6 +40,7 @@ export type Uppercase<Str extends string> = Str extends `${infer Char}${infer Ch
     : Str
 
 /**
+ * TODO: add example
  * Converts a string to lowercase
  */
 export type Lowercase<Str extends string> = Str extends `${infer Char}${infer Characters}`
@@ -48,6 +50,7 @@ export type Lowercase<Str extends string> = Str extends `${infer Char}${infer Ch
     : Str
 
 /**
+ * TODO: add example and fix the type
  * Capitalizes the first letter of a word and converts the rest to lowercase
  */
 export type Capitalize<Str extends string, FirstWord extends boolean = true> = Str extends `${infer Char}${infer Characters}`

diff --git a/test/array-types.test.ts b/test/array-types.test.ts
@@ -164,3 +164,23 @@ describe("FlattenArrayType", () => {
         expectTypeOf<utilities.FlattenArrayType<unknown[][][][]>>().toEqualTypeOf<unknown>()
     })
 })
+
+describe("ToUnion", () => {
+    test("Create an union type", () => {
+        expectTypeOf<utilities.ToUnion<12>>().toEqualTypeOf<12>()
+        expectTypeOf<utilities.ToUnion<"foo">>().toEqualTypeOf<"foo">()
+        expectTypeOf<utilities.ToUnion<12 | 21>>().toEqualTypeOf<12 | 21>()
+        expectTypeOf<utilities.ToUnion<[12, 21, "foo"]>>().toEqualTypeOf<12 | 21 | "foo" | []>()
+    })
+})
+
+describe("Includes", () => {
+    test("Check if an element exist withins a tuple", () => {
+        expectTypeOf<utilities.Includes<[], any>>().toEqualTypeOf<false>()
+        expectTypeOf<utilities.Includes<[1, 2, "foo", "bar"], 2>>().toEqualTypeOf<true>()
+        expectTypeOf<utilities.Includes<["foo", "bar", () => void, {}], () => void>>().toEqualTypeOf<true>()
+        expectTypeOf<utilities.Includes<[string, 1, () => void, {}], string>>().toEqualTypeOf<true>()
+        expectTypeOf<utilities.Includes<[string, number, () => void, {}], number>>().toEqualTypeOf<true>()
+        expectTypeOf<utilities.Includes<[true, false, true], number>>().toEqualTypeOf<false>()
+    })
+})
diff --git a/test/object-types.test.ts b/test/object-types.test.ts
@@ -168,15 +168,6 @@ describe("MergeAll", () => {
     })
 })
 
-describe("ToUnion", () => {
-    test("Create an union type", () => {
-        expectTypeOf<utilities.ToUnion<12>>().toEqualTypeOf<12>()
-        expectTypeOf<utilities.ToUnion<"foo">>().toEqualTypeOf<"foo">()
-        expectTypeOf<utilities.ToUnion<12 | 21>>().toEqualTypeOf<12 | 21>()
-        expectTypeOf<utilities.ToUnion<[12, 21, "foo"]>>().toEqualTypeOf<12 | 21 | "foo" | []>()
-    })
-})
-
 describe("AddPropertyToObject", () => {
     test("Append a new property of an exist object type", () => {
         expectTypeOf<utilities.AddPropertyToObject<{ foo: string }, "bar", number>>().toEqualTypeOf<{
@@ -252,17 +243,6 @@ describe("Parameters", () => {
     })
 })
 
-describe("Includes", () => {
-    test("Check if an element exist withins a tuple", () => {
-        expectTypeOf<utilities.Includes<[], any>>().toEqualTypeOf<false>()
-        expectTypeOf<utilities.Includes<[1, 2, "foo", "bar"], 2>>().toEqualTypeOf<true>()
-        expectTypeOf<utilities.Includes<["foo", "bar", () => void, {}], () => void>>().toEqualTypeOf<true>()
-        expectTypeOf<utilities.Includes<[string, 1, () => void, {}], string>>().toEqualTypeOf<true>()
-        expectTypeOf<utilities.Includes<[string, number, () => void, {}], number>>().toEqualTypeOf<true>()
-        expectTypeOf<utilities.Includes<[true, false, true], number>>().toEqualTypeOf<false>()
-    })
-})
-
 describe("ObjectEntries", () => {
     test("Returns the entries from an object", () => {
         expectTypeOf<utilities.ObjectEntries<{ foo: string }>>().toEqualTypeOf<["foo", string]>()