feat(asyncFirstOnce): add asyncFirstOnce function

djcsdy · djcsdy · commit c68f34944ffc · 2022-10-28T03:23:57.000+01:00
diff --git a/index.ts b/index.ts
@@ -86,3 +86,13 @@ export async function asyncToSetOnce<T>(iterator: AsyncIteratorLike<T>): Promise
     }
     return set;
 }
+
+export async function asyncFirstOnce<T>(iterator: AsyncIteratorLike<T>): Promise<T | null> {
+    const it = asyncIterator(iterator);
+    const element = await it.next();
+    if (element.done === true) {
+        return null;
+    } else {
+        return element.value;
+    }
+}

Original file line number	Diff line number	Diff line change
`@@ -86,3 +86,13 @@ export async function asyncToSetOnce<T>(iterator: AsyncIteratorLike<T>): Promise`
`86`	`86`	`}`
`87`	`87`	`return set;`
`88`	`88`	`}`
	`89`	`+`
	`90`	`+export async function asyncFirstOnce<T>(iterator: AsyncIteratorLike<T>): Promise<T \| null> {`
	`91`	`+ const it = asyncIterator(iterator);`
	`92`	`+ const element = await it.next();`
	`93`	`+ if (element.done === true) {`
	`94`	`+ return null;`
	`95`	`+ } else {`
	`96`	`+ return element.value;`
	`97`	`+ }`
	`98`	`+}`