clocksy - npm Package Compare versions

Comparing version 1.0.0 to 1.1.0

CHANGELOG.md

 # Changelog
 
+## 1.1.0 (Jul 14, 2016)
+
+* **Disable automatic updates when tab is hidden**.
+* Give external access to the estimated round-trip time (`getRtt()`).
+* Improve docs.
+
 ## 1.0.0 (Jul 13, 2016)
 
 * First public release.

lib/index.js

@@ -44,3 +44,3 @@ 'use strict';
       type: 'CLOCKSY',
-      data: clocksy.processRequest(msg.data),
+      data: clocksy.processRequest(data),
     });
@@ -93,6 +93,9 @@ return;
   if (type === 'CLOCKSY') {
-    const tDelta = clocksy.processResponse(msg.data);
+    const tDelta = clocksy.processResponse(data);
     // tDelta is the estimated server time minus the local time.
-    // Use this dekta for whatever purpose you want
-    // (you can also get it later on with clocksy.getDelta())
+    // Use this delta for whatever purpose you want, e.g.
+    // correcting the local time for graphs or changing the timestamps
+    // of data downloaded from the server...
+    // If you don't need the delta immediately, you can also obtain it later
+    // calling clocksy.getDelta())
     return;
@@ -107,2 +110,4 @@ }
   function ClocksyClient() {
+    var _this = this;
+
     var _ref = arguments.length <= 0 || arguments[0] === undefined ? {} : arguments[0];
@@ -119,2 +124,3 @@
     this.tDelta = null;
+    this.rtt = null;
     this.timer = null;
@@ -124,2 +130,14 @@ this.alpha = alpha;
     this.sendRequest = sendRequest || function () {};
+
+    // Keep track of the tab's shown/hidden status. Chrome
+    // goes bonkers with the timers in hidden windows, so RTT
+    // calculations are not reliable. Automatic requests are
+    // not sent while the tab is hidden.
+    this.fHiddenTab = false;
+    try {
+      this.fHiddenTab = document.hidden;
+      document.addEventListener('visibilitychange', function () {
+        _this.fHiddenTab = document.hidden; // change tab text for demo
+      });
+    } catch (err) {/* ignore */}
   }
@@ -142,2 +160,3 @@
       this.tDelta = this.calcNewDelta(tDelta);
+      this.rtt = rtt;
       return this.tDelta;
@@ -159,6 +178,11 @@ }
   }, {
+    key: 'getRtt',
+    value: function getRtt() {
+      return this.rtt;
+    }
+  }, {
     key: 'start',
     value: function start() {
       if (this.timer != null) this.stop();
-      this.sendAutoRequest();
+      this.sendAutoRequest(true);
       this.timer = setInterval(this.sendAutoRequest.bind(this), this.updatePeriod);
@@ -175,3 +199,4 @@ }
     key: 'sendAutoRequest',
-    value: function sendAutoRequest() {
+    value: function sendAutoRequest(fForce) {
+      if (this.fHiddenTab && !fForce) return;
       var req = this.createRequest();
@@ -178,0 +203,0 @@ this.sendRequest(req);

libEs6/index.js

@@ -33,3 +33,3 @@ /*!
       type: 'CLOCKSY',
-      data: clocksy.processRequest(msg.data),
+      data: clocksy.processRequest(data),
     });
@@ -72,6 +72,9 @@ return;
   if (type === 'CLOCKSY') {
-    const tDelta = clocksy.processResponse(msg.data);
+    const tDelta = clocksy.processResponse(data);
     // tDelta is the estimated server time minus the local time.
-    // Use this dekta for whatever purpose you want
-    // (you can also get it later on with clocksy.getDelta())
+    // Use this delta for whatever purpose you want, e.g.
+    // correcting the local time for graphs or changing the timestamps
+    // of data downloaded from the server...
+    // If you don't need the delta immediately, you can also obtain it later
+    // calling clocksy.getDelta())
     return;
@@ -89,2 +92,3 @@ }
     this.tDelta = null;
+    this.rtt = null;
     this.timer = null;
@@ -94,2 +98,14 @@ this.alpha = alpha;
     this.sendRequest = sendRequest || (() => {});
+
+    // Keep track of the tab's shown/hidden status. Chrome
+    // goes bonkers with the timers in hidden windows, so RTT
+    // calculations are not reliable. Automatic requests are
+    // not sent while the tab is hidden.
+    this.fHiddenTab = false;
+    try {
+      this.fHiddenTab = document.hidden;
+      document.addEventListener('visibilitychange', () => {
+        this.fHiddenTab = document.hidden; // change tab text for demo
+      });
+    } catch (err) { /* ignore */ }
   }
@@ -107,2 +123,3 @@
     this.tDelta = this.calcNewDelta(tDelta);
+    this.rtt = rtt;
     return this.tDelta;
@@ -118,9 +135,8 @@ }
 
-  getDelta() {
-    return this.tDelta;
-  }
+  getDelta() { return this.tDelta; }
+  getRtt() { return this.rtt; }
 
   start() {
     if (this.timer != null) this.stop();
-    this.sendAutoRequest();
+    this.sendAutoRequest(true);
     this.timer = setInterval(this.sendAutoRequest.bind(this),
@@ -136,3 +152,4 @@ this.updatePeriod);
 
-  sendAutoRequest() {
+  sendAutoRequest(fForce) {
+    if (this.fHiddenTab && !fForce) return;
     const req = this.createRequest();
@@ -139,0 +156,0 @@ this.sendRequest(req);

package.json

 {
   "name": "clocksy",
-  "version": "1.0.0",
+  "version": "1.1.0",
   "description": "Transport-agnostic client-server clock synchronization",
@@ -10,5 +10,9 @@ "main": "lib/index.js",
     "clock",
+    "time",
     "synchronization",
     "sync",
-    "rtt"
+    "rtt",
+    "client",
+    "server",
+    "ntp"
   ],
@@ -15,0 +19,0 @@ "homepage": "https://github.com/guigrpa/clocksy#readme",

README.md

@@ -8,5 +8,7 @@ # clocksy [![npm version](https://img.shields.io/npm/v/clocksy.svg)](https://www.npmjs.com/package/clocksy)
 
-* Simplicity
-* Automatic requests, typically converging to few ms
-* Transport-agnostic: use it with HTTP, WebSockets, MQTT, whatever.
+* **Simple algorithm**: timestamp at the client, timestamp at the server and send back, measure round-trip time, estimate server time and apply an [IIR filter](https://en.wikipedia.org/wiki/Infinite_impulse_response) to improve accuracy over time.
+* **Transport-agnostic**: use it on top of your own transport layer: HTTP, WebSockets, MQTT, whatever.
+* **Simple implementation**: since it leaves transport on the user's hands, it is exactly 5 LOCs for the server, ~70 for the client.
+* **Automatic requests**, typically converging to < 10 ms in a few iterations.
+* **Automatic background tab detection**: Chrome goes bonkers with –sorry, optimizes– timers on background tabs, interfering with clocksy's algorithm. Automatic clock updates are switched off while a tab is hidden.
 
@@ -38,3 +40,3 @@
       type: 'CLOCKSY',
-      data: clocksy.processRequest(msg.data),
+      data: clocksy.processRequest(data),
     });
@@ -67,6 +69,9 @@ return;
   if (type === 'CLOCKSY') {
-    const tDelta = clocksy.processResponse(msg.data);
+    const tDelta = clocksy.processResponse(data);
     // tDelta is the estimated server time minus the local time.
-    // Use this dekta for whatever purpose you want
-    // (you can also get it later on with clocksy.getDelta())
+    // Use this delta for whatever purpose you want, e.g.
+    // correcting the local time for graphs or changing the timestamps
+    // of data downloaded from the server...
+    // If you don't need the delta immediately, you can also obtain it later
+    // calling clocksy.getDelta())
     return;
@@ -78,2 +83,7 @@ }
 
+## Related
+
+* [timesync](https://github.com/enmasseio/timesync): provides more functionalities, but is apparently more complex.
+
+
 ## [Changelog](https://github.com/guigrpa/clocksy/blob/master/CHANGELOG.md)
@@ -80,0 +90,0 @@

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License

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Found 1 instance in 1 package

Fixed alerts

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Found 1 instance in 1 package

Improved metrics

Total package byte prevSize

22351

increased by14.33%

Lines of code

318

increased by13.98%

Number of lines in readme file

97

increased by11.49%

No dependency changes