Add Result.isSuccess/isFailure (#94)

block · Jun 24, 2024 · 0e8be4b · 0e8be4b
1 parent 2a7dcef
commit 0e8be4b
Show file tree

Hide file tree

Showing 4 changed files with 29 additions and 1 deletion.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+### Added
+* Adds `Result<T>.isSuccess(predicate: (T) -> Boolean): Boolean` and `Result<T>.isFailure(predicate: (Throwable) -> Boolean): Boolean` (Jem Mawson)
+
 ## [0.5.6] - 2024-06-21
 
 ### Added

diff --git a/lib/api/lib.api b/lib/api/lib.api
@@ -278,6 +278,8 @@ public final class app/cash/quiver/extensions/ResultKt {
 	public static final fun failure (Ljava/lang/Throwable;)Ljava/lang/Object;
 	public static final fun flatTap (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;)Ljava/lang/Object;
 	public static final fun flatten (Ljava/lang/Object;)Ljava/lang/Object;
+	public static final fun isFailure (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;)Z
+	public static final fun isSuccess (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;)Z
 	public static final fun mapFailure (Ljava/lang/Object;Lkotlin/jvm/functions/Function1;)Ljava/lang/Object;
 	public static final fun orThrow (Ljava/lang/Object;)Ljava/lang/Object;
 	public static final fun success (Ljava/lang/Object;)Ljava/lang/Object;

diff --git a/lib/src/main/kotlin/app/cash/quiver/extensions/Result.kt b/lib/src/main/kotlin/app/cash/quiver/extensions/Result.kt
@@ -22,7 +22,6 @@ fun <T> T.success(): Result<T> = Result.success(this)
  */
 fun <A> Throwable.failure(): Result<A> = Result.failure(this)
 
-
 /**
  * Turns a nullable value into a [Result].
  */
@@ -80,3 +79,15 @@ inline fun <A, B> Result<A>.tap(f: (A) -> B): Result<A> = this.map { a ->
 inline fun <A> Result<A>.flatTap(f: (A) -> Result<Any>): Result<A> = this.flatMap { a ->
   f(a).map { a }
 }
+
+/**
+ * Returns false if Success or returns the result of the given predicate to the Failure value.
+ */
+inline fun <T> Result<T>.isFailure(predicate: (Throwable) -> Boolean): Boolean =
+  fold(onFailure = predicate, onSuccess = { false })
+
+/**
+ * Returns false if Failure or returns the result of the given predicate to the Success value.
+ */
+inline fun <T> Result<T>.isSuccess(predicate: (T) -> Boolean): Boolean =
+  fold(onFailure = { false }, onSuccess = predicate)
diff --git a/lib/src/test/kotlin/app/cash/quiver/extensions/ResultTest.kt b/lib/src/test/kotlin/app/cash/quiver/extensions/ResultTest.kt
@@ -100,4 +100,16 @@ class ResultTest : StringSpec({
     e.failure<Int>().flatTap { Result.failure(Exception("broken")) }.shouldBeFailure(e)
   }
 
+  "Result.isFailure{}" {
+    Result.failure<String>(Exception("hello")).isFailure { it.message == "hello" } shouldBe true
+    Result.failure<String>(Exception("goodbye")).isFailure { it.message == "hello" } shouldBe false
+    "hello".success().isFailure { it.message == "hello" } shouldBe false
+  }
+
+  "Result.isSuccess{}" {
+    "hello".success().isSuccess { it == "hello" } shouldBe true
+    "goodbye".success().isSuccess { it == "hellow" } shouldBe false
+    Result.failure<String>(Exception("hello")).isSuccess { it == "hello" } shouldBe false
+  }
+
 })