We Keep Coding

How check idle activity using Javascript

Is there any default way in JavaScript to check user activity. If not how to address this issue.

There is no default way of doing this in java script. One way to address this issue is using JavaScript events.
this.lastActiveTime = new Date();
window.onclick = function () {
this.lastActiveTime= new Date();
};
window.onmousemove = function () {
this.lastActiveTime= new Date();
};
window.onkeypress = function () {
this.lastActiveTime= new Date();
};
window.onscroll = function () {
this.lastActiveTime= new Date();
};
let idleTimer_k = window.setInterval(CheckIdleTime, 10000);
function CheckIdleTime() {
//returns idle time every 10 seconds
let dateNowTime = new Date().getTime();
let lastActiveTime = new Date(this.lastActiveTime).getTime();
let remTime = Math.floor((dateNowTime-lastActiveTime)/ 1000);
// converting from milliseconds to seconds
console.log("Idle since "+remTime+" Seconds Last active at "+this.lastActiveTime)
}
<div> APP Here <br/><br/><br/><br/><br/><br/>make activity here<br/><br/><br/><br/><br/>Till here </div>

Here is the short example of the functionality where something will happen if user was inactive for around 10 minutes.
Upon init of the app:
window.lastActivity = Date.now();
document.addEventListener('click', function(){
window.lastActivity = Date.now();
})
Somewhere in particular service:
var TIMEOUT = 600000 //10 mins
var activityChecker = setInterval(check, 3000);
function check() {
var currentTime = Date.now();
if (currentTime - window.lastActivity > TIMEOUT) {
// do something useful, for example logout or whatever
}
}
This approach is nice because it doesn't depend on some timers which are working incorrectly if user minimize browser or switch to another tab, etc.
We just check current timestamp with the lastActivity timestamp every few seconds.
You can change 'click' event in my code with any other type of event you need or with any other condition which is suitable for you to consider user as active.

RRule JS weekday property not working as expected

I have written following code for getting daily recurrence in my angular, my issue is when I use byweekday property of RRule JS, application stuck and does not respond at all. Sometimes it does work but takes huge time to execute code on line #rrule_after. Please let me know why is this happening and what can be better solutions for this?
function getNextRecurrenceDate(recurrenceVo,rule){
var startDate = new Date(recurrenceVo.recurrenceRangeVO.startDate);
var today = new Date();
var calculatedDate = null;
if(today.getTime() <= startDate.getTime()){
return startDate;
}else{
//#rrule_after - when I debug the code and comes to this function execution, my application stucks/halts for long time and does not response at all
calculatedDate = rule.after(today,true);
// this is temporary code I have written to overcome the problem of daily weekday recurrence
if(calculatedDate && recurrenceVo.dailyRecurrenceVO && recurrenceVo.dailyRecurrenceVO.everyWeekDay && calculatedDate.getDay() > 4){
calculatedDate.setDate(calculatedDate.getDate() + (7 - calculatedDate.getDay()));
}
}
return (calculatedDate)?calculatedDate:'';
}
function getDailyNextRecurrenceDate(recurrenceVo){
var rule = new RRule({
freq: RRule.DAILY,
interval: recurrenceVo.dailyRecurrenceVO.numberofDays,
dtstart: new Date(recurrenceVo.recurrenceRangeVO.startDate)
})
if(recurrenceVo.recurrenceRangeVO.endCount){
rule.options.count = recurrenceVo.recurrenceRangeVO.endCount;
}
if(recurrenceVo.dailyRecurrenceVO.everyWeekDay){
rule.options.interval = 1;
// When I remove this code then all working fine and application not halting at all
rule.options.byweekday = [RRule.MO, RRule.TU, RRule.WE, RRule.TH, RRule.FR]
}
if(recurrenceVo.recurrenceRangeVO.endDate){
rule.options.until = new Date(recurrenceVo.recurrenceRangeVO.endDate);
}
var nextRecDate = getNextRecurrenceDate(recurrenceVo,rule);
return nextRecDate?nextRecDate.setHours(0,0,0,0):'';
}

how can I add the ticking clock to my div in an existing code?

It's actually a follow up to this question I want to display elements from json based on their time and duration and interval is interupted by settimeout - I accepted the answer there made by #Daniel Flint - his code is quite clear and can be found here http://jsfiddle.net/nauzilus/rqctam5r/
However, there's one more thing that I wanted to add - a simple div <div id="time"></div> that would contain a new date time object initialized during opening the page and then it being incremented every second just to show the current time constantly. I thought about writing there a javascript:
var actualTime = new Date(substractedDate); // taken from the server
function updateTimeBasedOnServer(timestamp) {
var calculatedTime = moment(timestamp);
var dateString = calculatedTime.format('h:mm:ss A');
$('#time').html(dateString + ", ");
};
var timestamp = actualTime.getTime();
updateTimeBasedOnServer(timestamp);
setInterval(function () {
timestamp += 1000; // Increment the timestamp at every call.
updateTimeBasedOnServer(timestamp);
}, 1000);
(I provide the time of the server as a timestamp there).
I just noticed that there is a slight mismatch between displaying the time in my div and between the text appearing on the screen, possibly because I increment both of the values in two different places.
So my question is - how can I "merge" #Daniel Flint's code with mine and increment both values only in one place?

One thing that jumps out here:
timestamp += 1000;
setTimeout/setInterval aren't guaranteed to run at precisely the delay you've entered. Run this in your browsers console:
var last = Date.now(),
time = function() {
var now = Date.now();
console.log(now - last);
last = now;
},
id = setInterval(time, 1000);
On my Mac at home (Chrome/FireFox) it was anywhere from 990 to 1015. Windows machine at work is a bit better (995-1002), but IE was getting up to 1020. It's not a huge difference, but it's not nothing.
So code needs to be able to handle not running exactly every 1000ms. That's why I was running the timer at 500ms intervals, and checking if the start time was less-than-equal to the current time.
I've rejigged the demo to show the time and message in sync:
(function() {
var messages = [];
var time = document.getElementById("current-time");
var display = document.getElementById("message");
function check() {
showMessage(currentMessage());
showTime();
}
function currentMessage() {
var message = null;
if (messages.length) {
var now = toTheSecond(new Date());
var start = toTheSecond(new Date(messages[0].start_time));
var end = toTheSecond(new Date(start.getTime() + ( messages[0].text_duration * 1000 )));
if (start <= now) {
if (end <= now) {
// done with the current message...
messages = messages.slice(1);
// ...but check if there's another one ready to go right now
message = currentMessage();
}
else {
message = messages[0];
}
}
}
return message;
}
function toTheSecond(date) {
date.setMilliseconds(0);
return date;
}
function showMessage(message) {
if (message) {
display.textContent = message.text_content;
}
else {
display.textContent = "no messages";
}
}
function showTime() {
time.textContent = new Date().toLocaleString()
}
function getMessages() {
setTimeout(function() {
var now = new Date();
messages.push(
{"text_content":"aaaaa","text_duration":5,"start_time": new Date(now.getTime() + 3000).toISOString()},
{"text_content":"aawwaaaaa","text_duration":5,"start_time": new Date(now.getTime() + 10000).toISOString()},
{"text_content":"bbaawwaaaaa","text_duration":5,"start_time": new Date(now.getTime() + 15000).toISOString()}
);
}, 1000);
}
setInterval(check, 500);
getMessages();
})();
<span id="current-time"></span> <span id="message">Hello there!</span>
(Putting the code here as well because I recall SO want code in the answers so it's controlled, but there's a demo here: http://jsfiddle.net/nauzilus/ymp0615g/).
This probably isn't as efficient as it could be; the message text is being set every iteration which might cause repaints/reflow. But then again setting the time stamp is going to do that anyway, so meh :)

Candy Crush Saga Type countdown life system jQuery & Phonegap

I'm developing an app and I'm interested in ways to achive a Candy Crush Saga Type countdown life system.
My app is developed in phonegap (so html, css jquery and jquery mobile) and untill now I havn't figured out how to work with an external file as I'm thinking it's needed in this algorithm.
I want therefore to have 5 lives and each of them dissapears when the user fail or quit the lvl and regenerates after, lets say, 10 minutes. How can I keep the counter active if the app is closed?
Or a date substraction algorithm...
If somebody have knowledge in Phonegap I would be very grateful if he could help me with a jsfiddle wich I'll implement further in my app.
I'm also not sure what to use: localstorage vs DB
I'll give 50 of my bounty for the one who can help me with a jsfiddle example for this issue.
Thank you!

Edit: Sorry this is some pseudo code based off PHP - but you don't need crazy algorithms or anything
I don't write phone apps, but I know what you're trying to do and you're thinking about it too hard. You don't need to run the counter while the app is closed. You can save a timestamp from when the game is over, and reference it the next time the app is opened.
start_game();
if($lives > 0){ //run game
if($death === true){
$lives = $lives - 1;
$timer_value = date(Y-m-d h:i:s);
end_game($timer_value); //save starting time locally in "end_game" function
}
} else {
//buy more lives
}
Now let's say the user closes it and opens up. You can reference the current time versus the saved time. For every 10 minutes past then, add a life.
$old_time = strtotime($timer_value); //635393400
$cur_time = strtotime(date(Y-m-d h:i:s)); //635394600
if( $cur_time - $old time > 600 ) { $lives = $lives + 1; }
if( $cur_time - $old time > 1200 ) { $lives = $lives + 2; }
if( $cur_time - $old time > 1800 ) { $lives = $lives + 3; }
if( $cur_time - $old time > 2400 ) { $lives = $lives + 4; }
if( $cur_time - $old time > 3000 ) { $lives = $lives + 5; }
if( $lives > 5 ) { $lives = 5; }
That's some awful code lol, but you gut the idea. You don't need to run a timer in the background (you can't really with the app being closed, without doing some sort of server checks online, which is basically the same thing, but hosting all that personal life records in the cloud instead of on the phone.

In this code I use the localStorage since they are available on all platforms and web.
Using local storage you will get better cross platform compatibility:
WebStorage (localStorage & sessionStorage)
IndexedDB
SQL-Storage
Localstorage is array, but every element can only have string in it (using JSON we can store anything, that is not recursive). It is about 5MB for web. I guess it is limitless for mobile app. SessionStorage is deleted when user close browser and I am not sure how it will do on mobile.
Just a small date validator...
Date.prototype.isValid = function(first_argument) {
if ( Object.prototype.toString.call(this) !== "[object Date]" )
return false;
return !isNaN(this.getTime());
}
The main var declaration among retrieving variables from localStorage
var timeout = null;
var maxlife = 5;
if (undefined === localStorage.life) {
localStorage.life = maxlife;
}
if (undefined === localStorage.date||localStorage.date=="") {
localStorage.date = "";
var date = null;
}else{
var date = new Date(Number(localStorage.date));
if(!date.isValid()){
date = null;
}
}
var timeoutTime = 5 * 60000;
var life = Number(localStorage.life);
Lose life, set date if none exist yet. Set a timeout too and subtract life (& write it into localstorage).
function loseLife() {
if (null === date) {
date = new Date();
localStorage.date = date.getTime();
timeout = setTimeout(function(){addLife()}, timeoutTime);
}
life--;
localStorage.life = life;
lives.innerHTML = life;
console.log(life);
}
Add life, set date new date or reset the date completely. Set a timeout, if needed, and add a life (& write it into localstorage).
function addLife() {
life++;
localStorage.life = life;
if (life < maxlife) {
date = new Date();
localStorage.date = date.getTime();
timeout = setTimeout(function(){addLife()}, timeoutTime);
} else {
date = null;
localStorage.date = "";
}
lives.innerHTML = life;
}
Here you may need to change the hooks for blur (window not visible) and focus (window visible once again). Blur just clear timeout so it don't mess with us.
window.addEventListener('blur', function () {
clearTimeout(timeout);
});
This function check how many time it can subtract our time needed to get life from difference of now and the date we lost a life.
function tillNow(){
if (life < maxlife&&date!=null) {
var d = new Date();
var diff = d - date;
while (diff - timeoutTime > 0) {
diff = diff - timeoutTime;
if (life < maxlife) {
life++;
console.log("add");
}else{
date = null;
localStorage.date = "";
break;
}
}
localStorage.life = life;
if (life < maxlife) {
date = new Date((new Date()).getTime()-diff);
localStorage.date = date.getTime();
timeout = setTimeout(function(){addLife()}, timeoutTime-diff);
}
}
lives.innerHTML = life;
}
Focus just call tillNow()
window.addEventListener('focus', function () {
tillNow();
});
Onload do the same as focus, but fills the div with a value initially...
window.onload=function(){
var lives = document.getElementById("lives");
lives.innerHTML = life;
tillNow();
}
Demo sorry couldn't do jsFiddle of codepen since they don't like local storage. (the demo use 15sec as timer to get new life ;) I am impatient )

I would use logic similar to what Xhynk suggested. I would use a variable like milisecondsUntilYouGainALife and when you lose the first life, set this variable = 1000ms*60sec*10min = 600000. Then first line (or so) in main loop, record the current time. next time it hits the loop also record the time and subtract the difference from milisecondsUntilYouGainALife. If < 0, lives++. Also make sure in your "close the app" function you record the time and check that time in the main loop.
pseudocode:
function game(){
...
while(mainLoop){
oldTime = curTime
curTime = GetTime() //I Forget the exact code to get the miliseconds
deltaTime = curTime - oldTime
if(deltaTime > milisectionsUntilYouGainALife){
if(lives < MAX_LIVES){
lives++
milisecondsUntilYouGainALife - deltaTime
}
}
}
}
function AppClosing(){
curTime = GetTime()
}
function LoseALife(){
milisecondsUntilYouGainALife += 600000
}
There may be something im missing, but this should get you on the right track!

Difference of defining a variable inside and outside a function

New to javascript here.
The Team Treehouse blog has a small tutorial on how to build a timer in javascript. It is basically the following code:
<h1 id="timer">Loading</h1>
var updateMessage = function(){
var date = Date();
var message = document.getElementById("timer");
message.innerHTML = "The time is " + date;
}
var timer = setInterval(updateMessage, 500);
This works fine and all. However I want to use date for multiple functions. I tried the following..
var date = Date();
var updateMessage = function(){
var message = document.getElementById("timer");
message.innerHTML = "The time is " + date;
}
..but now it doesn't work realtime. Whenever I hit F5 it gives back the correct time but it's not updated realtime anymore.
Why is this? I thought that when I declare a variable outside of a function, it would become a global function which could be used anywhere.

Because Date() is the time you call it, it does not keep updating!
If you want to share it, update it inside of the function.
var date;
var updateMessage = function(){
date = new Date();
var message = document.getElementById("timer");
message.innerHTML = "The time is " + date;
}

var date = Date();
var updateMessage = function(){
var message = document.getElementById("timer");
message.innerHTML = "The time is " + date;
}
in above case var date is a variable whose value is assigned when script loaded.
and in another case var date is assign all time when the updateMessage is called
var updateMessage = function(){
var date = Date();
var message = document.getElementById("timer");
message.innerHTML = "The time is " + date;
}

var date = Date();
Is only executed once when script loads. The variable date stays the same throughout the lifetime of the webpage. That is why it only changes when you refresh the page.

The problem here is not where you define the date variable but where and how many times you are calling the Date() function.
Declaring it globally but making the necessary call everytime you need is also a valid solution.
var date; // declaration
var updateMessage = function(){
var message = document.getElementById("timer");
date = Date(); // call to Date() everytime updateMessage is executed
message.innerHTML = "The time is " + date;
}

Well you are missing setInterval in second example?
Apart from that, you were on the right track, but with a little problem: The way you are doing it now, you are getting the Date() when you load the page, and just use the same date over and over.
Something like this should work for you, as it would give you a global variable while changing the date dinamically:
var date = Date();
var updateMessage = function(){
date = Date();
var message = document.getElementById("timer");
message.innerHTML = "The time is " + date;
}