event-loop-spinner - npm Package Compare versions

Comparing version 2.1.0 to 2.2.0

dist/event-loop-spinner.js

 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
 exports.EventLoopSpinner = void 0;
+const immediately = typeof setImmediate === 'function'
+    ? setImmediate
+    : (cb) => cb();
 class EventLoopSpinner {
@@ -13,3 +16,3 @@ constructor(thresholdMs = 10) {
     async spin() {
-        return new Promise((resolve) => setImmediate(() => {
+        return new Promise((resolve) => immediately(() => {
             this.afterLastSpin = Date.now();
@@ -16,0 +19,0 @@ resolve();

lib/event-loop-spinner.ts

@@ -0,1 +1,6 @@
+const immediately =
+  typeof setImmediate === 'function'
+    ? setImmediate
+    : (cb: () => void): void => cb();
+
 export class EventLoopSpinner {
@@ -14,3 +19,3 @@ private afterLastSpin: number;
     return new Promise((resolve) =>
-      setImmediate(() => {
+      immediately(() => {
         this.afterLastSpin = Date.now();
@@ -17,0 +22,0 @@ resolve();

package.json

 {
   "name": "event-loop-spinner",
-  "version": "2.1.0",
+  "version": "2.2.0",
   "description": "Tiny helper to prevent blocking Node.js event loop",
@@ -5,0 +5,0 @@ "main": "dist/index.js",

README.md

@@ -19,4 +19,28 @@ # event-loop-spinner
 
+
 ## Reading
 
 [Node.js: How even quick async functions can block the Event-Loop, starve I/O](https://snyk.io/blog/nodejs-how-even-quick-async-functions-can-block-the-event-loop-starve-io/)
+
+
+## How does this help?
+
+Node can only run one bit of JS at a time. While it is running this bit of JS, it does nothing else.
+It doesn't fire timers. It doesn't accept TCP connections from clients.
+
+In fact, Node doesn't even do these things when it finishes running one bit of JS. It prefers to
+immediately run the next bit of JS. It does this for "a while".
+
+This gives you two amazingly powerful ways to shoot yourself in the foot; it's great! Just like C++.
+
+That is, if some node process either:
+ * contains some JS code which runs for "too long", or
+ * handles too many concurrent work items, resulting in lots of JS to run,
+
+..then it won't handle network requests, or let anyone else do any JS. This can result in the
+application appearing unresponsive for seconds or minutes. (Yes, we really see minutes.)
+
+`event-loop-spinner` masks this problem. The `spin()` method allows Node to stop running this JS
+function, and its friends, and do some other JS, or do some IO. This significantly shortens the
+time before more networking is done (i.e. a response is sent to a client), and/or other people's
+JS is run, improving responsiveness.

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Improved metrics

Total package byte prevSize

8332

increased by21.39%

Lines of code

158

increased by4.64%

Number of lines in readme file

46

increased by109.09%

No dependency changes