Chunk difference methods (#2658)

Co-authored-by: Tim <hello@timsmart.co>

.changeset/four-garlics-wonder.md

@@ -0,0 +1,5 @@
+---
+"effect": minor
+---
+
+add Chunk.difference & Chunk.differenceWith

packages/effect/src/Chunk.ts

@@ -1387,3 +1387,33 @@ export const reduceRight: {
   <B, A>(b: B, f: (b: B, a: A, i: number) => B): (self: Chunk<A>) => B
   <A, B>(self: Chunk<A>, b: B, f: (b: B, a: A, i: number) => B): B
 } = RA.reduceRight
+
+/**
+ * Creates a `Chunk` of values not included in the other given `Chunk` using the provided `isEquivalent` function.
+ * The order and references of result values are determined by the first `Chunk`.
+ *
+ * @since 3.2.0
+ */
+export const differenceWith = <A>(isEquivalent: (self: A, that: A) => boolean): {
+  (that: Chunk<A>): (self: Chunk<A>) => Chunk<A>
+  (self: Chunk<A>, that: Chunk<A>): Chunk<A>
+} => {
+  return dual(
+    2,
+    (self: Chunk<A>, that: Chunk<A>): Chunk<A> => unsafeFromArray(RA.differenceWith(isEquivalent)(that, self))
+  )
+}
+
+/**
+ * Creates a `Chunk` of values not included in the other given `Chunk`.
+ * The order and references of result values are determined by the first `Chunk`.
+ *
+ * @since 3.2.0
+ */
+export const difference: {
+  <A>(that: Chunk<A>): (self: Chunk<A>) => Chunk<A>
+  <A>(self: Chunk<A>, that: Chunk<A>): Chunk<A>
+} = dual(
+  2,
+  <A>(self: Chunk<A>, that: Chunk<A>): Chunk<A> => unsafeFromArray(RA.difference(that, self))
+)

packages/effect/test/Chunk.test.ts

@@ -17,6 +17,8 @@ describe("Chunk", () => {
     expect(Chunk.unsafeFromNonEmptyArray).exist
     expect(Chunk.contains).exist
     expect(Chunk.containsWith).exist
+    expect(Chunk.difference).exist
+    expect(Chunk.differenceWith).exist
     expect(Chunk.findFirst).exist
     expect(Chunk.findFirstIndex).exist
     expect(Chunk.findLast).exist
@@ -874,4 +876,25 @@ describe("Chunk", () => {
     expect(equivalence(Chunk.make(1, 2, 3), Chunk.make(1, 2))).toBe(false)
     expect(equivalence(Chunk.make(1, 2, 3), Chunk.make(1, 2, 4))).toBe(false)
   })
+
+  it("differenceWith", () => {
+    const eq = <E extends { id: number }>(a: E, b: E) => a.id === b.id
+    const diffW = pipe(eq, Chunk.differenceWith)
+
+    const curr = Chunk.make({ id: 1 }, { id: 2 }, { id: 3 })
+
+    expect(diffW(Chunk.make({ id: 1 }, { id: 2 }), curr)).toEqual(Chunk.make({ id: 3 }))
+    expect(diffW(Chunk.empty(), curr)).toEqual(curr)
+    expect(diffW(curr, Chunk.empty())).toEqual(Chunk.empty())
+    expect(diffW(curr, curr)).toEqual(Chunk.empty())
+  })
+
+  it("difference", () => {
+    const curr = Chunk.make(1, 3, 5, 7, 9)
+
+    expect(Chunk.difference(Chunk.make(1, 2, 3, 4, 5), curr)).toEqual(Chunk.make(7, 9))
+    expect(Chunk.difference(Chunk.empty(), curr)).toEqual(curr)
+    expect(Chunk.difference(curr, Chunk.empty())).toEqual(Chunk.empty())
+    expect(Chunk.difference(curr, curr)).toEqual(Chunk.empty())
+  })
 })