From 06cf6df954f0ab745bccb9455e7da14104acf1ae Mon Sep 17 00:00:00 2001
From: Steven Guerrero <stephenguerrero43@gmail.com>
Date: Mon, 16 Nov 2020 18:20:46 -0500
Subject: [PATCH] feat(std/node): Add util.deprecate (#8407)

---
 std/node/_util.ts     | 16 ++++++++++++++++
 std/node/util_test.ts | 25 +++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/std/node/_util.ts b/std/node/_util.ts
index 9cf9966701..b217435416 100644
--- a/std/node/_util.ts
+++ b/std/node/_util.ts
@@ -123,6 +123,22 @@ export function getSystemErrorName(code: number): string | undefined {
   return errorMap.get(code)?.[0];
 }
 
+/**
+ * https://nodejs.org/api/util.html#util_util_deprecate_fn_msg_code
+ * @param _code This implementation of deprecate won't apply the deprecation code
+ */
+export function deprecate<A extends Array<unknown>, B>(
+  this: unknown,
+  callback: (...args: A) => B,
+  msg: string,
+  _code?: string,
+) {
+  return function (this: unknown, ...args: A) {
+    console.warn(msg);
+    return callback.apply(this, args);
+  };
+}
+
 import { _TextDecoder, _TextEncoder } from "./_utils.ts";
 
 /** The global TextDecoder */
diff --git a/std/node/util_test.ts b/std/node/util_test.ts
index 9db463b99e..d9c05f8a5d 100644
--- a/std/node/util_test.ts
+++ b/std/node/util_test.ts
@@ -220,3 +220,28 @@ Deno.test({
     }
   },
 });
+
+Deno.test("[util] deprecate", () => {
+  const warn = console.warn.bind(null);
+
+  let output;
+  console.warn = function (str: string) {
+    output = str;
+    warn(output);
+  };
+
+  const message = "x is deprecated";
+
+  const expected = 12;
+  let result;
+  const x = util.deprecate(() => {
+    result = expected;
+  }, message);
+
+  x();
+
+  assertEquals(expected, result);
+  assertEquals(output, message);
+
+  console.warn = warn;
+});