Develop Reference

jQuery prevent reload if button clicked

I have a jQuery datatable that immediately loads ON READY. After that, the datatable is reloaded every 30 seconds. This feature is functioning properly.
I have added a search feature that automatically reloads the datatable with new search results. This part is also functioning properly.
The problem I am experiencing is when I am using the search feature, and the new search results are returned. After 30 seconds, the new results are cleared and the datatable reloads with all of the original records.
Here is what I am currently attempting:
$(document).ready(function()
{
var searchCriteria = "";
displayBookings(searchCriteria);
var idle = 0;
var idleInterval = setInterval(timer, 30000);
$(this).mousemove(function(e){idle = 0;});
$(this).keypress(function(e){idle = 0;});
function timer()
{
idle = idle + 1;
if(idle > 2)
{
displayBookings(searchCriteria);
console.log('table reloaded');
}
}
$('#searchPending').on('click', function()
{
var isPending = 'Y';
var searchCriteria = {
isPending: isPending
};
displayBookings(searchCriteria);
});
});
The function displayBookings() takes searchCriteria. If searchCriteria is blank, then a basic query is fired. Obviously is searchCriteria contains parameters, then the same query is fired with a WHERE clause attached. I did not disclose the code for displayBookings().
All I need to do is stop the 30 second interval if the #searchPending button is clicked.

Clear the interval so it will stop loading.
clearInterval(idleInterval)
specifically in your code:
$('#searchPending').on('click', function()
{
clearInterval(idleInterval)
var isPending = 'Y';
var searchCriteria = {
isPending: isPending
};
displayBookings(searchCriteria);
});

Rather than start and stop the timer interval, since you'll run into a bit of a race condition, you can just have the "refresh" (your "timer" function) refresh using the latest search criteria. To do this, just pass the same object into your displayBookings function. E.g.
const search = { criteria: "" };
$(...).click(() => {
search.criteria = 'change it...';
displayBookings(search.criteria);
});
setInterval(() => displayBookings(search.criteria), 30000);
This way, if a refresh happens, it will use the latest search.criteria. You can achieve the same result with minimal change in your code by simply removing the var from the second searchCriteria. Currently, without removing the var, your outer criteria is being "shadowed" by your inner.
I alluded to debouncing1 in one of my comments. I misread the code and debouncing is not what you want. Instead, you want to only "refresh" if there hasn't been any user activity within some threshold. Here's an alternative from the approach you used:
let lastInteraction = 0;
function interact() {
lastInteraction = Date.now();
}
$(this).mousemove(interact);
$(this).keypress(interact);
Then in your refresh function:
if (Date.now() - lastInteraction > threshold) { ...
Implementing both the central criteria and revised idle check:
$(document).ready(function() {
const idle = {
threshold: 1000,
lastInteraction: 0,
interact() {
idle.lastInteraction = Date.now();
},
isIdle() {
return Date.now() - idle.lastInteraction > idle.threshold;
}
};
const search = { criteria: "" };
$(this).mousemove(idle.interact);
$(this).keypress(idle.interact);
setInterval(() => {
if (idle.isIdle()) {
displayBookings(search.criteria);
}
}, 30000);
$('#searchPending').on('click', () => {
search.criteria = { isPending: 'Y' };
displayBookings(search.criteria);
});
displayBookings(search.criteria);
});
1 The Wikipedia article linked to discusses debouncing with a keyboard. It's the same concept. You'd use debouncing on your displayBookings function if you plan on having it execute live as the user is typing. This would prevent too many HTTP requests from happening in a short duration of time.

Simplest possible irrevocable timout / cooldown function?

I'm trying to add a 1 second cooldown to my send-message system (as in, you can send 1 message per second max). So my initial thought was simply to create a timeout, and before attempting in sending to check if it exists still. That turned out to take more line of code than I anticipated initially.
Is there something I'm missing here? Isn't there something as simple as:
//inside some message sending function
if(!mySuperCooldown)
{
//send message
mySuperCooldown = cooldown(1000);
}
Everything else I construct successfully ends up taking loads of lines, and it appears to me as something someone thought of before. Thank you, and excuse my illiteracy.

Have a flag that allows messages, and set it to false when a message is sent. Then set a timeout for 1000 milliseconds that resets the flag to true.
var allowMessage = true;
function sendMessage(msg) {
if (allowMessage) {
//do something
allowMessage = false;
setTimeout(() => allowMessage = true, 1000);
}
}

Make a higher order function that turns a normal function into one that is rate limited:
function rate_limit(delay, func) {
var last_call = null;
return function() {
if (last_call && (Date.now() - last_call <= delay)) {
return;
}
last_call = Date.now();
return func();
};
}
You can then rate limit any function:
var my_function = rate_limit(1000, function() {
console.log('foo');
});
Running my_function() will only call your original function once per second.

How can I wait for a condition?

I'm new on protractor, and I'm trying to implement an e2e test.
I don't know if this is the right way to do this, but...
The page that I want to test is not a full angular page based, so... I'm having some trouble.
On my first spec I have:
describe('should open contact page', function() {
var ptor = protractor.getInstance();
beforeEach(function(){
var Login = require('./util/Login');
new Login(ptor);
});
I have created this Login class, but after login I want to open the contact page, but protractor immediately try to find element before the page is fully loaded.
I've tried to use:
browser.driver.wait(function() {
expect(browser.findElement(by.xpath("//a[#href='#/contacts']")).isDisplayed());
ptor.findElement(by.xpath("//a[#href='#/contacts']")).click();
});
But it doesn't work... it always try to find the element before the page loads.
I tried this one too:
browser.driver.wait(function() {
expect(ptor.isElementPresent(by.xpath("//a[#href='#/contacts']")));
ptor.findElement(by.xpath("//a[#href='#/contacts']")).click();
});
I'm able to do that using browser.sleep(); but I don't think that is a good option. Any idea? On my login class I have:
ptor.ignoreSynchronization = true;
How can I wait for this #href='#/contacts before protractor tries to click on it?

Protractor 1.7.0 has also introduced a new feature: Expected Conditions.
There are several predefined conditions to explicitly wait for. In case you want to wait for an element to become present:
var EC = protractor.ExpectedConditions;
var e = element(by.id('xyz'));
browser.wait(EC.presenceOf(e), 10000);
expect(e.isPresent()).toBeTruthy();
See also:
Expected conditions in protractor

I finally find out...
var waitLoading = by.css('#loading.loader-state-hidden');
browser.wait(function() {
return ptor.isElementPresent(waitLoading);
}, 8000);
expect(ptor.isElementPresent(waitLoading)).toBeTruthy();
var openContact = by.xpath("//a[#href='#/contacts']");
element(openContact).click();
With this protractor could wait for that element until it loading page disappears.
Thanks for those who tried to help XD.

I had the same problem you were having for the longest time while using protractor. In my e2e test I start in a non angular app, then get into an angular portion, then get back out to a non angular portion. Made things tricky. The key is to understand promises and how they work. Here's some examples of my real world code in a functioning e2e test. Hoping this gives you an idea of how to structure your tests. Probably some bad practice in this code, please feel free to improve upon this, but I know that it works, maybe not the best way.
To get to angular I use
var ptor;
var events = require('events');
var eventEmitter = new events.EventEmitter();
var secondClick = require('./second-click');
beforeEach(function () {
browser.driver.get('http://localhost:8080/');
},10000);
it("should start the test", function () {
describe("starting", function () {
it("should find the link and start the test", function(){
var elementToFind = by.linkText('Start'); //what element we are looking for
browser.driver.isElementPresent(elementToFind).then(function(isPresent){
expect(isPresent).toBe(true); //the test, kind of redundant but it helps pass or fail
browser.driver.findElement(elementToFind).then(function(start){
start.click().then(function(){ //once we've found the element and its on the page click it!! :)
ptor = protractor.getInstance(); //pass down protractor and the events to other files so we can emit events
secondClick(eventEmitter, ptor); //this is your callback to keep going on to other actions or test in another file
});
});
});
});
});
},60000);
While in angular this code works
describe("type in a message ", function(){
it("should find and type in a random message", function(){
var elementToFind = by.css('form textarea.limited');
browser.driver.isElementPresent(elementToFind).then(function(isPresent){
element(elementToFind).sendKeys(randomSentence).then(function(){
console.log("typed in random message");
continueOn();
});
});
});
},15000);
After exiting angular
browser.driver.wait(function(){
console.log("polling for a firstName to appear");
return browser.driver.isElementPresent(by.name('firstName')).then(function(el){
return el === true;
});
}).
then(function(){
somefunctionToExecute()
});
Hope that gives some guidance and helps you out!

browser.driver.wait(function() {
return browser.driver.isElementPresent(by.xpath("//a[#href='#/contacts']"));
});
This works for me too (without the timeout param)..
for more information, see http://angular.github.io/protractor/#/api?view=webdriver.WebDriver.prototype.wait

Thanks to answers above, this was my simplified and updated usage
function waitFor (selector) {
return browser.wait(function () {
return browser.isElementPresent(by.css(selector));
}, 50000);
}

Have you tried putting the ng-app in the <html> tag (assuming this part of code is under your control)? This solved a lot of initialization timing problems for me.

Best way to use wait conditions in protractor that helps to show proper error message to particular element if test case failed
const EC = ExpectedConditions;
const ele = element(by.xpath(your xpath));
return browser.wait(EC.visibilityOf(ele),9000,'element not found').then(() => {
ele.click();
});

I'm surprised that nobody has added this solution. Basically, if you are using modal dialogues you often get an element visible and available to click but not being clickable due to the modal dialogue being in front of it. This happens because protractor moves faster than angular and is ready to click the next element while angular is still closing the modal.
I suggest using
public async clickElementBug(elementLocator: Locator) {
const elem = await element(elementLocator);
await browser.wait(
async function() {
try {
await elem.click();
return true;
} catch (error) {
return false;
}
},
this.TIMEOUT_MILLIS,
'Clicking of element failed: ' + elem
);
}

browser.wait may sound too ordinary, but it's not!
browser.wait is the way to go. Just pass a function to it that would have a condition which to wait for. For example wait until there is no loading animation on the page
let $animation = $$('.loading');
await browser.wait(
async () => (await animation.count()) === 0, // function; if returns true it stops waiting; can wait for anything in the world if you get creative with it
5000, // timeout
`message on timeout` // comment on error
);
Make sure to use await
You can also use existing library called ExpectedConditions that has lots of predefined conditions to wait for
You can't imagine what you can do with it...
A few of my favorite ones:
wait until the number of browser's tab's is 2
// wait until the number of browser's tab's is 2
await browser.wait(
async () => {
let tabCount = await browser.getAllWindowHandles();
return tabCount.length === 2;
},
5000,
'the url didnt open in a new window'
);
wait until the loading animation is gone for at last 750ms
// wait until the loading animation is gone for at last 750ms
await browser.wait(
async () => (await this.$$loadAnimations.count()) === 0 && !(await browser.sleep(750)) && (await this.$$loadAnimations.count()) === 0,
5000,
`waiting timeout`
);
wait for ANY number of elements to be present
// wait for any number of elements to be present
async waitForElements($elem, timeout = 120000, start = +new Date()) {
let conditions = [];
for (let i = 0; i < $elem.length; i++) {
conditions.push(ExpectedConditions.presenceOf($elem[i]));
}
await browser.wait(
ExpectedConditions.and(...conditions),
remainingTimeout(timeout, start),
`wait for all elements`
);
}
// and use
await waitForElements([
$usernameField,
$passwordFiend,
$submitButton
])

How to stop and restart collection observers in Meteor?

I want to be able to stop and restart observers on my collections in Meteor.
Imagine I have the following observer:
// Imagine some collection of Blog posts "Posts"
Posts.find().observe({
changed: notifySubscribedUsers
});
// function notifySubscribedUsers() { ... }
// is some function that will email everyone saying some post was updated
Now imagine I want to update lots of Posts, but I dont want the observers to be called. How can I get access to the observers, stop/pause them and then later restart them (after the db job is finished) ?
TIA

The observer returns a handle:
var handle = Posts.find().observe({
changed: notifySubscribedUsers
});
Then you can stop it with:
handle.stop()
It's not possible to 'pause' it in the conventional sense, if you want to pause it you could just ignore the data it gives you.
To do this in a neat wrapped up method you could do something like:
var handle;
var start = function() {
if(handle) handle.stop();
var handle = Posts.find().observe({
changed: notifySubscribedUsers
});
}
var stop = function() { if(handle) handle.stop }
Or to put it on a collection:
// posts.js collection file
Posts.startObservers = function startObservers() {
Posts.observer = Posts.find().observe({
change: notifySubscribedUsers // or some other function
});
};
Posts.stopObservers = function stopObservers() {
if(Posts.observer) {
Posts.observer.stop(); // Call the stop
}
};
// Trigger Somewhere else in the code
Posts.stopObservers();
MyTool.doWorkOnPosts(); // Some contrived work on the Posts collection
Posts.startObservers();

javascript WAIT for something to be true

i create in a javascript function a prototype window. in the window i load a site where the user has to select something. i want the javascript function to wait until the user selected something and then return the value of the what the user selected.
function showTargetDirectoryChooser(){
var win = new Window( 'dirchooser_' + new Date().getTime() , {className: 'alphacube', width: 320, height: 470, url: '/directories/choose', maximizable: false});
win.showCenter();
win.setDestroyOnClose();
// WAIT_UNTIL( win.content.contentWindow.Directory != null )
return win.content.contentWindow.Directory
}
i found here something i could maybe use - but i dont understand how to...

This is an asynchronous process; it’s probably better to handle this with a callback.
For example, couldn’t you use a closeCallback?
function showTargetDirectoryChooser(done){
var win = new Window( 'dirchooser_' + new Date().getTime() , {className: 'alphacube', width: 320, height: 470, url: '/directories/choose', maximizable: false});
win.showCenter();
win.setDestroyOnClose();
// This will ensure
win.setCloseCallback(function () {
done(win.content.contentWindow.Directory);
return true; // or return false if you don't want the window to be closed
});
return true;
}
With this, you would change
var chosenDir = showTargetDirectoryChooser();
// do something with chosen directory
into
var chosenDir;
showTargetDirectoryChooser(function (directory) {
chosenDir = directory;
// do something with the chosen directory
});

One option would be to use an event handler. When Directory is set via click or perhaps a change event, if that is fired, attach a handler which takes that event and passes it back to a function in your main window. This will require making your code asynchronous - so that you have a caller that calls showTargetDirectoryChooser() and a callback that takes the result of the directory as separate functions. It shouldn't be too complicated to re-architect your code there and break it up to the caller and the callback, though.
You can also use setTimeout and poll the contents of win.content.contentWindow.Directory like so:
function showTargetDirectoryChooser(){
var win = new Window( 'dirchooser_' + new Date().getTime() , {className: 'alphacube', width: 320, height: 470, url: '/directories/choose', maximizable: false});
win.showCenter();
win.setDestroyOnClose();
setTimeout("pollDirectory()", 500); // poll in a half second
}
function pollDirectory() {
if(win.content.contentWindow.Directory != null) {
callback(win.content.contentWindow.Directory); // you will need an asynch callback
} else {
setTimeout("pollDirectory()", 500); // poll in a half second
}
}
Doing it this way also requires that your code be asynchronous.
Another option is to look into jquery wait, but that is a timeout as opposed to waiting on a condition. Or there is a set of reactive extensions to JS, but that looks to be overkill for what you are doing. The concept of an observable may be something you want to look into, though.