Merge 715a8a7 into a2cf595

myty · Sep 24, 2022 · 2fc068e · 2fc068e
2 parents a2cf595 + 715a8a7
commit 2fc068e
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Showing 5 changed files with 64 additions and 18 deletions.
diff --git a/README.md b/README.md
@@ -81,7 +81,7 @@ console.log(`Result: propertyOne=${propertyOne}, propertyTwo=${propertyTwo}`);
 With PromiseChain, it is simplified and easier to read.
 
 ```typescript
-const { propertyOne, propertyTwo } = await Composable.create(testClass)
+const { propertyOne, propertyTwo } = await chain(testClass)
   .asyncIncrement("propertyOne", 3)
   .asyncIncrement("propertyTwo", 5)
   .increment("propertyTwo", 5);

diff --git a/promise-chain.bench.ts b/promise-chain.bench.ts
@@ -1,4 +1,4 @@
-import { PromiseChain } from "./promise-chain.ts";
+import { chain } from "./promise-chain.ts";
 import { TestClass } from "./stubs/test-class.ts";
 
 const iterate = (
@@ -18,7 +18,7 @@ Deno.bench(
 Deno.bench(
   "Composable Async Chain (1 Step)",
   { group: "1 step" },
-  iterate((t) => PromiseChain.create(t).asyncIncrement("propertyOne", 3)),
+  iterate((t) => chain(t).asyncIncrement("propertyOne", 3)),
 );
 
 Deno.bench(
@@ -35,7 +35,7 @@ Deno.bench(
   "Composable Async Chain (2 Steps)",
   { group: "2 steps" },
   iterate((t) =>
-    PromiseChain.create(t).asyncIncrement("propertyOne", 3).increment(
+    chain(t).asyncIncrement("propertyOne", 3).increment(
       "propertyTwo",
       5,
     )
@@ -60,7 +60,7 @@ Deno.bench(
   "Composable Async Chain (6 Steps)",
   { group: "6 steps" },
   iterate((t) =>
-    PromiseChain.create(t)
+    chain(t)
       .asyncIncrement("propertyOne", 3)
       .asyncIncrementTwo()
       .asyncIncrementOne()

diff --git a/promise-chain.test.ts b/promise-chain.test.ts
@@ -1,8 +1,14 @@
 import {
   assert,
   assertEquals,
+  assertRejects,
 } from "https://deno.land/std@0.154.0/testing/asserts.ts";
-import { PromiseChain } from "./promise-chain.ts";
+import {
+  assertSpyCalls,
+  spy,
+} from "https://deno.land/std@0.157.0/testing/mock.ts";
+import PromiseChain, { chain } from "./promise-chain.ts";
+import { TestClassWithException } from "./stubs/test-class-with-exceptions.ts";
 import { TestClass } from "./stubs/test-class.ts";
 
 Deno.test(async function whenTraditionalAsyncChainingItReturnsResult() {
@@ -28,7 +34,7 @@ Deno.test(async function whenAsyncChainingItReturnsResult() {
   const testClass = new TestClass();
 
   // Act
-  const result = await PromiseChain.create(testClass)
+  const result = await chain(testClass)
     .asyncIncrement("propertyOne", 3)
     .asyncIncrementTwo()
     .asyncIncrementOne()
@@ -46,7 +52,7 @@ Deno.test(function whenComposableAsyncItIsPromise() {
   const testClass = new TestClass();
 
   // Act
-  const result = PromiseChain.create(testClass);
+  const result = chain(testClass);
 
   // Assert
   assert(result instanceof PromiseChain);
@@ -57,7 +63,7 @@ Deno.test(async function whenChainedPromiseIsReusedItReturnsCachedResult() {
   // Arrange
   const testClass = new TestClass();
   const durationExpectedMs = 250;
-  const resultTask = PromiseChain.create(testClass)
+  const resultTask = chain(testClass)
     .asyncIncrement("propertyTwo", 3)
     .asyncIncrementOneLongRunningTask(durationExpectedMs);
   await resultTask;
@@ -76,3 +82,39 @@ Deno.test(async function whenChainedPromiseIsReusedItReturnsCachedResult() {
   assertEquals(resultTwo.propertyOne, 1);
   assertEquals(resultTwo.propertyTwo, 6);
 });
+
+Deno.test(function whenPromiseChainHasExceptionItIsRejected() {
+  // Arrange
+  const testClassWithException = new TestClassWithException();
+
+  // Act, Assert
+  assertRejects(() => chain(testClassWithException).throwException());
+});
+
+Deno.test(async function whenPromiseChainHasExceptionItIsCaught() {
+  // Arrange
+  const catchSpy = spy();
+  const testClassWithException = new TestClassWithException();
+
+  // Act
+  await chain(testClassWithException)
+    .throwException()
+    .catch(catchSpy);
+
+  // Assert
+  assertSpyCalls(catchSpy, 1);
+});
+
+Deno.test(async function whenPromiseChainPromiseIsFinalized() {
+  // Arrange
+  const finallySpy = spy();
+  const testClass = new TestClass();
+
+  // Act
+  await chain(testClass)
+    .asyncIncrementOne()
+    .finally(finallySpy);
+
+  // Assert
+  assertSpyCalls(finallySpy, 1);
+});
diff --git a/promise-chain.ts b/promise-chain.ts
@@ -4,17 +4,10 @@ import { AsyncComposable } from "./types.ts";
  * Utility class to wrap a composition class with the intended purpose of chaining methods, specifically useful for
  * functions that return Promises. Note: Promise functions and non-promise functions can be mixed.
  */
-export class PromiseChain<T> extends Promise<T> implements Promise<T> {
-  /**
-   * Create a chaninable class based off of the functions that return "this" or a Promise of "this".
-   */
-  static create<T>(wrappedClass: T): AsyncComposable<T> {
-    return new PromiseChain(wrappedClass) as unknown as AsyncComposable<T>;
-  }
-
+export default class PromiseChain<T> extends Promise<T> implements Promise<T> {
   private _valuePromise: Promise<T>;
 
-  private constructor(_wrappedClass: T) {
+  constructor(_wrappedClass: T) {
     super((_resolve, _reject) => {});
 
     this._valuePromise = Promise.resolve(_wrappedClass);
@@ -55,3 +48,9 @@ export class PromiseChain<T> extends Promise<T> implements Promise<T> {
     return keys as Array<keyof T>;
   }
 }
+
+export function chain<T>(wrappedObj: T) {
+  return new PromiseChain(wrappedObj) as unknown as
+    & PromiseChain<T>
+    & AsyncComposable<T>;
+}
diff --git a/stubs/test-class-with-exceptions.ts b/stubs/test-class-with-exceptions.ts
@@ -0,0 +1,5 @@
+export class TestClassWithException {
+  throwException(): Promise<TestClassWithException> {
+    return Promise.reject();
+  }
+}