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Added CurrentValuePublisher.removeDuplicates(…) 
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Lines changed: 117 additions & 74 deletions

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‎Sources/CombineExtensions/CurrentValuePublisher/CurrentValuePublisher+RemoveDuplicates.swift‎

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import Combine
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extension CurrentValuePublisher {
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/// Returns a new `CurrentValuePublisher` that emits values only when they differ from the
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/// previous value, as determined by the provided predicate.
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///
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/// - Parameter predicate: A closure that compares the previous and current values and returns
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/// `true` if they are considered duplicates.
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/// - Returns: A `CurrentValuePublisher` that emits only distinct values.
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public func removeDuplicates(
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by predicate: @escaping (Output, Output) -> Bool
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) -> CurrentValuePublisher<Output, Failure> {
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switch self.storage {
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case .constant:
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return self
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case .subject:
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let initialValue = self.value
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let upstream = self.dropFirst()
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.drop { predicate(initialValue, $0) }
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.removeDuplicates(by: predicate)
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return CurrentValuePublisher(
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initial: initialValue,
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upstream: upstream
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)
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}
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}
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}
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extension CurrentValuePublisher where Output: Equatable {
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/// Returns a new `CurrentValuePublisher` that emits values only when they differ from the
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/// previous value.
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///
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/// - Returns: A `CurrentValuePublisher` that emits only distinct values.
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public func removeDuplicates() -> CurrentValuePublisher<Output, Failure> {
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return self.removeDuplicates(by: ==)
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}
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}

‎Tests/CombineExtensionsTests/CurrentValuePublisher/CurrentValuePublisherTests.swift‎

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@@ -605,80 +605,80 @@ class CurrentValuePublisherTests: XCTestCase {
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XCTAssertEqual(values, ["10", "11", "20", "12", "30", "30", "12"])
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}
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// // ============================================================================ //
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// // MARK: - Remove Duplicates Operator
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// // ============================================================================ //
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//
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// func testRemoveDuplicates_constant() {
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// var cancellables = Set<AnyCancellable>()
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// var values = [Int]()
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//
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// CurrentValuePublisher(value: 1)
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// .removeDuplicates()
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// .sink { values.append($0) }
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// .store(in: &cancellables)
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//
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// XCTAssertEqual(values, [1])
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// }
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//
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// func testRemoveDuplicates_subject() {
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// var cancellables = Set<AnyCancellable>()
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// var values = [Int]()
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//
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// let subject = CurrentValueSubject<Int, Never>(1)
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//
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// CurrentValuePublisher(subject)
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// .removeDuplicates()
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// .sink { values.append($0) }
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// .store(in: &cancellables)
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//
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// XCTAssertEqual(values, [1])
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//
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// subject.send(1)
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// XCTAssertEqual(values, [1])
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//
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// subject.send(1)
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// XCTAssertEqual(values, [1])
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//
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// subject.send(2)
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// XCTAssertEqual(values, [1, 2])
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//
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// subject.send(2)
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// XCTAssertEqual(values, [1, 2])
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//
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// subject.send(3)
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// XCTAssertEqual(values, [1, 2, 3])
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// }
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//
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// func testRemoveDuplicate_subject_customPredicate() {
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// var cancellables = Set<AnyCancellable>()
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// var values = [Int]()
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//
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// let subject = CurrentValueSubject<Int, Never>(1)
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//
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// CurrentValuePublisher(subject)
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// .removeDuplicates(by: { old, new in new < old })
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// .sink { values.append($0) }
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// .store(in: &cancellables)
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//
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// XCTAssertEqual(values, [1])
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//
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// subject.send(4)
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// XCTAssertEqual(values, [1, 4])
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//
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// subject.send(3)
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// XCTAssertEqual(values, [1, 4])
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//
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// subject.send(6)
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// XCTAssertEqual(values, [1, 4, 6])
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//
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// subject.send(2)
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// XCTAssertEqual(values, [1, 4, 6])
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//
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// subject.send(7)
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// XCTAssertEqual(values, [1, 4, 6, 7])
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// }
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//
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// ============================================================================ //
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// MARK: - Remove Duplicates Operator
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// ============================================================================ //
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func testRemoveDuplicates_constant() {
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var cancellables = Set<AnyCancellable>()
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var values = [Int]()
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CurrentValuePublisher(value: 1)
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.removeDuplicates()
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.sink { values.append($0) }
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.store(in: &cancellables)
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XCTAssertEqual(values, [1])
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}
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func testRemoveDuplicates_subject() {
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var cancellables = Set<AnyCancellable>()
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var values = [Int]()
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let subject = CurrentValueSubject<Int, Never>(1)
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CurrentValuePublisher(subject)
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.removeDuplicates()
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.sink { values.append($0) }
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.store(in: &cancellables)
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XCTAssertEqual(values, [1])
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subject.send(1)
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XCTAssertEqual(values, [1])
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subject.send(1)
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XCTAssertEqual(values, [1])
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subject.send(2)
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XCTAssertEqual(values, [1, 2])
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subject.send(2)
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XCTAssertEqual(values, [1, 2])
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subject.send(3)
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XCTAssertEqual(values, [1, 2, 3])
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}
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func testRemoveDuplicate_subject_customPredicate() {
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var cancellables = Set<AnyCancellable>()
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var values = [Int]()
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let subject = CurrentValueSubject<Int, Never>(1)
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CurrentValuePublisher(subject)
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.removeDuplicates(by: { old, new in new < old })
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.sink { values.append($0) }
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.store(in: &cancellables)
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XCTAssertEqual(values, [1])
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subject.send(4)
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XCTAssertEqual(values, [1, 4])
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subject.send(3)
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XCTAssertEqual(values, [1, 4])
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subject.send(6)
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XCTAssertEqual(values, [1, 4, 6])
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subject.send(2)
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XCTAssertEqual(values, [1, 4, 6])
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subject.send(7)
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XCTAssertEqual(values, [1, 4, 6, 7])
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}
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// // ============================================================================ //
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// // MARK: - CombineLatest Operator
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// // ============================================================================ //

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