feat(asyncEqualOnce): add asyncEqualOnce function

Author: djcsdy

index.test.ts

@@ -5,6 +5,7 @@ import {
     asyncDropUntilOnce,
     asyncDropWhileOnce,
     asyncEmptyOnce,
+    asyncEqualOnce,
     asyncInitialOnce,
     asyncIterator,
     asyncLastOnce,
@@ -284,3 +285,23 @@ test("asyncDropUntilOnce", async t => {
         [4, 3, 2, 1]
     );
 });
+
+test("asyncEqualOnce", async t => {
+    t.true(await asyncEqualOnce(asyncIterator([1, 2, 3]), asyncIterator([1, 2, 3])));
+    t.false(await asyncEqualOnce(asyncIterator([1, 2, 3]), asyncIterator([1, 2, 3, 4])));
+    t.false(await asyncEqualOnce(asyncIterator([1, 2, 3, 4]), asyncIterator([1, 2, 3])));
+    t.false(await asyncEqualOnce(asyncIterator([1, 3, 3]), asyncIterator([1, 2, 3])));
+    t.true(
+        await asyncEqualOnce(
+            asyncIterator([asyncIterator([1, 2]), asyncIterator([3, 4])]),
+            asyncIterator([asyncIterator([1, 2]), asyncIterator([3, 4])]),
+            asyncEqualOnce
+        )
+    );
+    t.false(
+        await asyncEqualOnce(
+            asyncIterator([asyncIterator([1, 2]), asyncIterator([3, 4])]),
+            asyncIterator([asyncIterator([1, 2]), asyncIterator([3, 4])])
+        )
+    );
+});

index.ts

@@ -1,3 +1,4 @@
+import {equal as defaultEqual} from "@softwareventures/ordered";
 import type {AsyncIterableLike} from "@softwareventures/async-iterable";
 import {hasProperty} from "unknown";
 import {asyncIterable} from "@softwareventures/async-iterable";
@@ -420,3 +421,30 @@ export function asyncDropUntilOnceFn<T>(
 ): (iterator: AsyncIteratorLike<T>) => AsyncIterator<T> {
     return iterator => asyncDropUntilOnce(iterator, predicate);
 }
+
+export async function asyncEqualOnce<T>(
+    a: AsyncIteratorLike<T>,
+    b: AsyncIteratorLike<T>,
+    elementsEqual: (a: T, b: T) => boolean | Promise<boolean> = defaultEqual
+): Promise<boolean> {
+    const ait = asyncIterator(a);
+    const bit = asyncIterator(b);
+    let aElement = await ait.next();
+    let bElement = await bit.next();
+    while (
+        aElement.done !== true &&
+        bElement.done !== true &&
+        (await elementsEqual(aElement.value, bElement.value))
+    ) {
+        aElement = await ait.next();
+        bElement = await bit.next();
+    }
+    return aElement.done === true && bElement.done === true;
+}
+
+export function asyncEqualOnceFn<T>(
+    b: AsyncIteratorLike<T>,
+    elementsEqual: (a: T, b: T) => boolean | Promise<boolean> = defaultEqual
+): (a: AsyncIteratorLike<T>) => Promise<boolean> {
+    return async a => asyncEqualOnce(a, b, elementsEqual);
+}

package.json

@@ -23,6 +23,7 @@
   },
   "dependencies": {
     "@softwareventures/async-iterable": "^1.0.1",
+    "@softwareventures/ordered": "^2.0.0",
     "tslib": "2.4.0",
     "unknown": "^0.2.5"
   },

yarn.lock

@@ -854,6 +854,7 @@ __metadata:
     "@commitlint/cz-commitlint": 17.1.2
     "@softwareventures/async-iterable": ^1.0.1
     "@softwareventures/eslint-config": 7.0.0
+    "@softwareventures/ordered": ^2.0.0
     "@softwareventures/precise-commits": 2.0.22
     "@softwareventures/prettier-config": 3.0.0
     "@softwareventures/semantic-release-config": 2.0.2
@@ -927,7 +928,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@softwareventures/ordered@npm:^1.1.0 || ^2.0.0":
+"@softwareventures/ordered@npm:^1.1.0 || ^2.0.0, @softwareventures/ordered@npm:^2.0.0":
   version: 2.0.0
   resolution: "@softwareventures/ordered@npm:2.0.0"
   dependencies: