From 8ab20a4582016542ac3d8140593f817ab920005f Mon Sep 17 00:00:00 2001
From: Steven Guerrero <stephenguerrero43@gmail.com>
Date: Mon, 16 Nov 2020 14:44:37 -0500
Subject: [PATCH] feat(std/node): implement process.nextTick (#8386)

---
 std/node/process.ts      | 20 ++++++++++++++++++++
 std/node/process_test.ts | 21 +++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/std/node/process.ts b/std/node/process.ts
index a47140f150..6f61a074a0 100644
--- a/std/node/process.ts
+++ b/std/node/process.ts
@@ -28,6 +28,25 @@ export const versions = {
   ...Deno.version,
 };
 
+/** https://nodejs.org/api/process.html#process_process_nexttick_callback_args */
+export function nextTick(this: unknown, cb: () => void): void;
+export function nextTick<T extends Array<unknown>>(
+  this: unknown,
+  cb: (...args: T) => void,
+  ...args: T
+): void;
+export function nextTick<T extends Array<unknown>>(
+  this: unknown,
+  cb: (...args: T) => void,
+  ...args: T
+) {
+  if (args) {
+    queueMicrotask(() => cb.call(this, ...args));
+  } else {
+    queueMicrotask(cb);
+  }
+}
+
 /** https://nodejs.org/api/process.html#process_process */
 // @deprecated `import { process } from 'process'` for backwards compatibility with old deno versions
 export const process = {
@@ -123,6 +142,7 @@ export const process = {
     // Getter also allows the export Proxy instance to function as intended
     return Deno.env.toObject();
   },
+  nextTick,
 };
 
 /**
diff --git a/std/node/process_test.ts b/std/node/process_test.ts
index 6e6145e677..ee566853e3 100644
--- a/std/node/process_test.ts
+++ b/std/node/process_test.ts
@@ -5,6 +5,7 @@ import { assert, assertEquals, assertThrows } from "../testing/asserts.ts";
 import * as path from "../path/mod.ts";
 import * as all from "./process.ts";
 import { argv, env } from "./process.ts";
+import { delay } from "../async/delay.ts";
 
 // NOTE: Deno.execPath() (and thus process.argv) currently requires --allow-env
 // (Also Deno.env.toObject() (and process.env) requires --allow-env but it's more obvious)
@@ -164,3 +165,23 @@ Deno.test({
     // assert(process.stderr.isTTY);
   },
 });
+
+Deno.test({
+  name: "process.nextTick",
+  async fn() {
+    let withoutArguments = false;
+    process.nextTick(() => {
+      withoutArguments = true;
+    });
+
+    const expected = 12;
+    let result;
+    process.nextTick((x: number) => {
+      result = x;
+    }, 12);
+
+    await delay(10);
+    assert(withoutArguments);
+    assertEquals(result, expected);
+  },
+});