Merge pull request #107 from UrbanCompass/skip-first

Observable Skip First

Snail/Observable.swift

@@ -115,6 +115,23 @@ public class Observable<T> : ObservableType {
         return observable
     }
 
+    public func skip(first: UInt) -> Observable<T> {
+        let observable = Observable<T>()
+        var count = first
+
+        subscribe(onNext: {
+            if count == 0 {
+                observable.on(.next($0))
+            }
+            count = UInt(max(Int(count) - 1, 0))
+        }, onError: {
+            observable.on(.error($0))
+        }, onDone: {
+            observable.on(.done)
+        })
+        return observable
+    }
+
     func notify(subscriber: Subscriber<T>, event: Event<T>) {
         guard let queue = subscriber.queue else {
             subscriber.handler(event)

SnailTests/ObservableTests.swift

@@ -238,4 +238,20 @@ class ObservableTests: XCTestCase {
             XCTAssert(received.first == "3")
         }
     }
+
+    func testSkipFirst() {
+        let observable = Observable<String>()
+        var received: [String] = []
+
+        observable.skip(first: 2).subscribe(onNext: { string in
+            received.append(string)
+
+            XCTAssert(received.count == 1)
+            XCTAssert(received.first == "3")
+        })
+
+        observable.on(.next("1"))
+        observable.on(.next("2"))
+        observable.on(.next("3"))
+    }
 }