EDIT: I think I should make things more obvious.
What I am trying to do is to make the function that displays the "time ago" from the submitted date of the post auto refresh every minute so that it stays relatively accurate even if the template is not re rendered.
I'd like to auto update my timeago value in my template but it is not working.
I've tried to set up my code with a reactive function, based on the answer to a similar question (https://stackoverflow.com/a/17933506)
Here's my code:
var timeAgoDep = new Deps.Dependency(); // !!!
var timeAgo;
var timeAgoInterval;
Template.postItem.created = function() {
function getTimeago() {
//var now = new Date();
timeAgo = moment(this.submitted).twitter();
timeAgoDep.changed(); // !!!
};
getTimeago(); /* Call it once so that we'll have an initial value */
timeAgoInterval = Meteor.setInterval(getTimeago, 5000);
};
Template.postItem.posted = function() {
timeAgoDep.depend(); // !!!
return timeAgo;
};
Template.postItem.destroyed = function() {
Meteor.clearInterval(timeAgoInterval);
};
I'm pretty sure that the problem comes from this.submitted because if I assign timeAgo = now for example, it will display the time and update like it's supposed to.
I also know that moment(this.submitted).twitter() works fine because when all I do is return it through a helper, it works.
A much better way to do this is to just embrace Meteor's reactivity and render time-dependent values reactively. In your case, the problem is that you are invalidating the dependency once every 5 seconds for each postItem rendered, which will quickly turn into a huge mess.
See https://github.com/mizzao/meteor-timesync for a package that provides reactive time variables on the client (and they are synced to server time too!) It's basically doing what you want, but in a cleaner way. (Disclaimer: I wrote this package.)
You can use moment in the same way to compute the actual string to display. For example, get rid of all the other stuff and just use
Template.postItem.posted = function() {
return moment(this.submitted).from(TimeSync.serverTime());
}
The moment().twitter() extension doesn't seem like a good choice because it only uses the current client time and doesn't allow you to pass in a specific (i.e. server-synced) time or reactive value.
Related
I've been working with Liferay 7 for a while and needed to create a feedback form with prefilled values. I created a feedback form and a page, where it's shown and where I could add Javascript.
The user clicks on a link ("Did you find this helpful? Yes/No") and it takes you to the feedback page with the page and answer as URL parameters.
URL: {feedback-page-url/} ?pageUrl=/services&answer=Yes
Now here's where the problems began. Liferay updates it's values very confusingly and while generic document.getElementsByName(...) etc. seemed to work at first, they updated back when clicking the page. The difficult thing is to update the right values in right elements, so they won't be overrun by Liferay.
I provided an answer to my question below. Feel free to ask me anything, I'll try to help :)
Full code block in the end!
So I found out a solution to this problem. Liferay creates an instance (_com_liferay...) and uses it's values to be up to date, so we need to get a hold of it and update it's values. You can do it manually by inspecting and finding your instance, but I have an automatic code that should get it for you.
The id we are searching for is for DDMFormPortlet and the String we get this way is close to perfect. The String that document.querySelector() finds begins with p_p_id_com..., so we can use .substring to remove the unnecessary part and then add +"form" in the end to make it complete. If you find a better way to find this, please share it :)
// _com_liferay_dynamic_data_mapping_form_web_portlet_DDMFormPortlet_INSTANCE_randomkey_form
const idFinder = function() {
const idString = document.querySelector('[id*="DDMFormPortlet"]').id;
return(idString.substring(6) + "form");
}
Now that we have the correct String text, we'll find the element, that corresponds to it:
const formFieldArray = window[idFinder()];
Now if you try it just by itself, it most likely won't find anything, because it's loads slowly. I put all of this into try-catch with setTimeout() to make sure everything works as intended. Now all we need to do is collect the information from our URL and set it to the correct places.
const params = new URLSearchParams(location.search);
const formAutoFiller = function (params) {
try {
const formFieldArray = window[idFinder()];
// make sure you have the numbers according to your form!
formFieldArray.pages[0].rows[0].columns[0].fields[0].value=params.get('pageUrl');
formFieldArray.pages[0].rows[1].columns[0].fields[0].value=params.get('answer');
// ...
}
}
And finally, as the changed values update to the form after clicking an input field, we'll move the selection focus to one of the input fields after the other code is ran:
document.getElementsByClassName("ddm-field-text")[1].focus();
A bit cleanup for myself and we're done! Full Javascript here:
const params = new URLSearchParams(location.search);
const idFinder = function() {
const idString = document.querySelector('[id*="DDMFormPortlet"]').id;
return(idString.substring(6) + "form");
}
const formAutoFiller = function (params) {
try {
const formFieldRows = window[idFinder()].pages[0].rows;
formFieldRows[0].columns[0].fields[0].value=params.get('pageUrl');
formFieldRows[1].columns[0].fields[0].value=params.get('answer');
document.getElementsByClassName("ddm-field-text")[1].focus();
} catch (e) {
setTimeout(formAutoFiller, 500, params);
}
}
formAutoFiller(params);
In my website I'm Showing my database after user has given the database name, Is there any way I can constantly update the web shown databasebase without refreshing the page . I've tried using setInterval but it's not working for some reason .
function c(){
setInterval(beta, 1000);
}
function beta(){
var d = document.getElementById("opopo").value;
var firebaseRefff= firebase.database().ref('LOCATION/'+d);
firebaseRefff.on('child_added', snap=> {
var slot=snap.getKey();
var alloted=snap.child("ALLOTED").val();
var date=snap.child("DATE").val();
var limit=snap.child("LIMIT").val();
var time=snap.child("TIME").val();
$("table tbody").append(""+slot+""+alloted+""+date+""+limit+""+time+"Null");
});
}
You do not need, and should not use, setInterval to trigger the queries. What you have in your beta() function looks pretty good.
firebaseRefff.on('child_added', snap => {}) means "whenever a child is added under this location, trigger the callback function (empty in my example) with the parameter 'snap'". It will also be called once, initially, for each child that is already at that database reference location.
You need to make sure you've called beta() once to setup this trigger.
If you're still having problems, you might want to insert logging to make sure beta() is being called, what the full reference path is, if the callback is ever triggered, and if your jquery string is correct.
I am developing a task application where the user inputs a task with a certain duration. I want to display a counter that shows for each task how much time the user has left. I have added the flyandi:reactive-countdown from the atmospherejs which works if I follow their example but in my case things are different. I have the following helper which returns the counter each seconds.
Template.tasks.helpers({
getCountdown: function() {
return countdown.get();
}
});
This is the counter variable which is GLOBAL otherwise it doesn't work.
var countdown = new ReactiveCountdown(30);
countdown.start(function() {
// do something when this is completed
});
As you can see in this case it uses a pre-defined value which is 30, but I want to use a variable. The problem is that the variable that I use to calculate how much time the user has left for that task is defined inside another function which makes her not accessible on a global scope. If I create that variable as global it doesn't work as it loads before the helper that I use to update its value.
Template.tasks.events({
'click #startTask':function(event){
console.log(this.taskName);
var duration=this.duration;
var numb = duration.match(/\d/g);
numb = numb.join("");
console.log(numb);
}
});
numb in this case is the time that the user has to finish the task but if I use something like new ReactiveCountdown(numb) this will display undefined as the script is run before the helper. Does anyone have any ideas?
I have a JSON data of news like this:
{
"news": [
{"title": "some title #1","text": "text","date": "27.12.15 23:45"},
{"title": "some title #2","text": "text","date": "26.12.15 22:35"},
...
]
}
I need to get a certain number of this list, depended on an argument in a function. As I understand, its called pagination.
I can get the ajax response and slice it immediately. So that every time the function is called - every time it makes an ajax request.
Like this:
function showNews(page) {
var newsPerPage = 5,
firstArticle = newsPerPage*(page-1);
xhr.onreadystatechange = function() {
if(xhr.readyState == 4) {
var newsArr = JSON.parse(xhr.responseText),
;
newsArr.news = newsArr.news.slice(firstArticle, newsPerPage*(page));
addNews(newsArr);
}
};
xhr.open("GET", url, true);
xhr.send();
Or I can store all the result in newsArr and slice it in that additional function addNews, sorted by pages.
function addNews(newsArr, newsPerPage) {
var pages = Math.ceil(amount/newsPerPages), // counts number of pages
pagesData = {};
for(var i=0; i<=pages; i++) {
var min = i*newsPerPages, //min index of current page in loop
max = (i+1)*newsPerPages; // max index of current page in loop
newsArr.news.forEach(createPageData);
}
function createPageData(item, j) {
if(j+1 <= max && j >= min) {
if(!pagesData["page"+(i+1)]) {
pagesData["page"+(i+1)] = {news: []};
}
pagesData["page"+(i+1)].news.push(item);
}
}
So, simple question is which variant is more effective? The first one loads a server and the second loads users' memory. What would you choose in my situation? :)
Thanks for the answers. I understood what I wanted. But there is so much good answers that I can't choose the best
It is actually a primarily opinion-based question.
For me, pagination approach looks better because it will not produce "lag" before displaying the news. From user's POV the page will load faster.
As for me, I would do pagination + preload of the next page. I.e., always store the contents of the next page, so that you can show it without a delay. When a user moves to the last page - load another one.
Loading all the news is definitely a bad idea. If you have 1000 news records, then every user will have to load all of them...even if he isn't going to read a single one.
In my opinion, less requests == better rule doesn't apply here. It is not guaranteed that a user will read all the news. If StackOverflow loaded all the questions it has every time you open the main page, then both StackOverflow and users would have huge problems.
If the max number of records that your service returns is around 1000, then I don't think it is going to create a huge payload or memory issues (by looking at the nature of your data), so I think option-2 is better because
number of service calls will be less
since user will not see any lag while paginating, his experience of using the site will be better.
As a rule of thumb:
less requests == better
but that's not always possible. You may run out of memory/network if the data you store is huge, i.e. you may need pagination on the server side. Actually server side pagination should be the default approach and then you think about improvements (e.g. local caching) if you really need them.
So what you should do is try all scenarios and see how well they behave in your concrete situation.
I prefer fetch all data but showing on some certain condition like click on next button data is already there just do hide and show on condition using jquery.
Every time call ajax is bad idea.
but you also need to call ajax for new data if data is changed after some periodic time
I need to do a simple pdf with some 3D objects for an oral presentation. I made several views, each one with a camera viewpoint, an object and a display mode.
To avoid the need to manually switch between the different viewpoints with the context menu, I would like the viewpoints to switch automatically with a Timer (each viewpoint staying for a few seconds). And I would like to not have to touch the mouse at all (nor the keyboard), so I would like to have the playback started as soon as the page appears.
I found the javascript command runtime.setView(N,x) to switch to the x'th view among N, but I don't know where to put it (I don't want to define a function which will be called when I press a button, since I want everything to be automated). Also, I don't know how to pause for a few seconds.
Any help ? Thanks !
I believe you're looking for setInterval(fn, time) which will call a function periodically at a time interval that you set. I'm not familiar with the setView() method you mentioned, but here's some pseudo code that you would put in tags at the end of the document body.
function startSwitcher()
var viewNum = 0;
var maxViews = 5; // you set this to how many views there are
setInterval(function() {
++viewNum;
if (viewNum >= maxViews) {
viewNum = 0;
}
runtime.setView(N, viewNum); // you will have to figure out this line
}, 2000);
}
startSwitcher();
The 2000 is 2000 milliseconds and is the time interval between executing the function. You can put any number of milliseconds there.
The runtime.setView(N, viewNum) line is something you will have to figure out as I am not familiar with whatever library you're trying to use there. The operative part of this code is the viewNum variable which configures which view in rotation should be next.
I think the runtime.SetView(..) Methods works with the name of the view as a string instead of the viewnumber. I have this function in a Dokument-level script and it works for me:
// view is the name of the view for example "TopView"
function setView(view){
console.println("Navigating to view: "+view);
var pageIndex = this.pageNum;
var annotIndex = 0;
var c3d = this.getAnnots3D( pageIndex )[ annotIndex ].context3D;
c3d.runtime.setView(view, true);
}
Combine this with the setInterval(..) from jfriend00´s answer und you should get what you need.
Best regards