From a4f27c4d570ad9b47bbd560fbf9b017f852fc29f Mon Sep 17 00:00:00 2001
From: Steven Guerrero <stephenguerrero43@gmail.com>
Date: Sat, 21 Nov 2020 16:13:18 -0500
Subject: feat(std/node): Add Readable Stream / Writable Stream / errors
 support (#7569)

---
 std/node/_utils.ts | 12 ++++++++++++
 1 file changed, 12 insertions(+)

(limited to 'std/node/_utils.ts')

diff --git a/std/node/_utils.ts b/std/node/_utils.ts
index b2745bf5a..cb91fac27 100644
--- a/std/node/_utils.ts
+++ b/std/node/_utils.ts
@@ -131,3 +131,15 @@ export function validateIntegerRange(
     );
   }
 }
+
+type OptionalSpread<T> = T extends undefined ? []
+  : [T];
+
+export function once(callback: (...args: OptionalSpread<undefined>) => void) {
+  let called = false;
+  return function (this: unknown, ...args: OptionalSpread<undefined>) {
+    if (called) return;
+    called = true;
+    callback.apply(this, args);
+  };
+}
-- 
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