AngularJS Infinite Scrolling with lots of data - javascript

So I'm trying to create an infinite scrolling table using AngularJS, similar to this: http://jsfiddle.net/vojtajina/U7Bz9/
The problem I'm having is that in the jsfiddle example, if I keep scrolling till I have a million results, the browser is going to slow to a crawl, wouldn't it? Because there would now be 1,000,000 results in $scope.items. It would be better if I only ever had, for example, 1000 results at a time inside $scope.items, and the results I was viewing happen to be within those 1000.
Example use case: page loads and I see the first 10 results (out of 1,000,000). Even though I only see 10, the first 1000 results are actually loaded. I then scroll to the very bottom of the list to see the last 10 items. If I scroll back up to the top again, I would expect that the top 10 results will have to be loaded again from the server.
I have a project I did with ExtJS that a similar situation: an infinite scrolling list with several thousand results in it. The ExtJS way to handle this was to load the current page of results, then pre-load a couple of extra pages of results as well. At any one time though, there was only ever 10 pages of results stored locally.
So I guess my question is how would I go about implementing this in AngularJS? I kow I haven't provided much code, so I'm not expecting people to just give the coded answer, but at least some advice in which direction to go.

A couple of things:
"Infinite scrolling" to "1,000,000" rows is likely to have issues regardless of the framework, just because you've created millions and millions of DOM nodes (presuming you have more than one element in each record)
The implementation you're looking at doing with <li ng-repeat="item in items">{{item.foo}}</li> or anything like that will have issues very quickly for one big reason: {{item.foo}}} or any ngBind like that will set up a $watch on that field, which creates a lot of overhead in the form of function references, etc. So while 10,000 small objects in an "array" isn't going to be that bad... 10,000-20,000 additional function references for each of those 10,000 items will be.
What you'd want to do in this case would be create a directive that handles the adding and removing of DOM elements that are "too far" out of view as well as keeping the data up to date. That should mitigate most performance issues you might have.
... good infinite scrolling isn't simple, I'm sorry to say.

I like the angular-ui implementation ui-scroll...
https://github.com/angular-ui/ui-scroll
... over ngInfiniteScroll. The main difference with ui-scroll from a standard infinite scroll is that previous elements are removed when leaving the viewport.
From their readme...
The common way to present to the user a list of data elements of undefined length is to start with a small portion at the top of the list - just enough to fill the space on the page. Additional rows are appended to the bottom of the list as the user scrolls down the list.
The problem with this approach is that even though rows at the top of the list become invisible as they scroll out of the view, they are still a part of the page and still consume resources. As the user scrolls down the list grows and the web app slows down.
This becomes a real problem if the html representing a row has event handlers and/or angular watchers attached. A web app of an average complexity can easily introduce 20 watchers per row. Which for a list of 100 rows gives you total of 2000 watchers and a sluggish app.
Additionally, ui-scroll is actively maintained.

It seems that http://kamilkp.github.io/angular-vs-repeat would be what you are looking for. It is a virtual scrolling directive.

So turns out that the ng-grid module for AngularJS has pretty much exactly what I needed. If you look at the examples page, the Server-Side Processing Example is also an infinite scrolling list that only loads the data that is needed.
Thanks to those who commented and answered anyway.
Latest URL : ng-grid

You may try using ng-infinite-scroll :
http://binarymuse.github.io/ngInfiniteScroll/

Check out virtualRepeat from Angular Material
It implements dynamic reuse of rows visible in the viewport area, just like ui-scroll

Related

Best practice to force the browser to only render user visible elements?

A particular page on our site loads with 1000s of divs each about 1000px x ~1500px(A printable page), each div displays additional elements/basic table/etc but can vary in height.
Render time can be several minutes depending on PC performance.
Using tools like webix which can load millions of rows proves the render process is taking up most of the loading time, but doesn't work well for non-tabular data.
Using Angular JS to create infinite scroll lists is possible. But this also doesn't work well with varying height elements.
All solutions I have found so far loose the browsers find feature, which our users commonly use, thus we will probably have to develop our own search tool.
Yes we could add pagination, or some sort of way of breaking down the data, but users still need to review all the data regardless of how it's broken down.
The same data (10,000 pages 30mb) once exported to PDF loads in < than 1 second.
I think the best solution will be the combination of a few different ideas.

Performance of searching through a list of items in javascript

I have a list of approx. 2000 questions and I am trying to create an interface where you can filter through them all using a text input.
I tried going through this React tutorial since i thought it would perform well enough but there is a considerable lag. Or at least there is when I run the code in an Electron container (perhaps I'd get better performance compiling it with Webpack). I just tried putting my code in to a jsfiddle and with 3000 elements the performance starts to suffer.
Is it futile trying to search through this many objects with html and js or is there a simpler way with better performance?
So the lag is not because of the filtering, but because you are trying to render too many objects in one hit. You can see this by typing a sequence of zeros into the filter input. Each zero typed requires less time, as obviously the result size gets smaller and smaller.
I have updated your fiddle here to show the performance if you only render the first 100 items in the result set (even though all 3000 are processed on each input change).
Essentially I am just generating the full rows variable, and then using .slice(0, 100) to generate a truncated version before rendering.
What you should do in this situation is think about UI/UX, and that it really isn't necessary to render thousands of items at the same time. You could implement some sort of pagination or infinite scroll, etc.

How to display large content quickly in browser [duplicate]

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I need to present a large number of rows of data (ie. millions of rows) to the user in a grid using JavaScript.
The user shouldn't see pages or view only finite amounts of data at a time.
Rather, it should appear that all of the data are available.
Instead of downloading the data all at once, small chunks are downloaded as the user comes to them (ie. by scrolling through the grid).
The rows will not be edited through this front end, so read-only grids are acceptable.
What data grids, written in JavaScript, exist for this kind of seamless paging?
(Disclaimer: I am the author of SlickGrid)
UPDATE
This has now been implemented in SlickGrid.
Please see http://github.com/mleibman/SlickGrid/issues#issue/22 for an ongoing discussion on making SlickGrid work with larger numbers of rows.
The problem is that SlickGrid does not virtualize the scrollbar itself - the scrollable area's height is set to the total height of all the rows. The rows are still being added and removed as the user is scrolling, but the scrolling itself is done by the browser. That allows it to be very fast yet smooth (onscroll events are notoriously slow). The caveat is that there are bugs/limits in the browsers' CSS engines that limit the potential height of an element. For IE, that happens to be 0x123456 or 1193046 pixels. For other browsers it is higher.
There is an experimental workaround in the "largenum-fix" branch that raises that limit significantly by populating the scrollable area with "pages" set to 1M pixels height and then using relative positioning within those pages. Since the height limit in the CSS engine seems to be different and significantly lower than in the actual layout engine, this gives us a much higher upper limit.
I am still looking for a way to get to unlimited number of rows without giving up the performance edge that SlickGrid currently holds over other implementations.
Rudiger, can you elaborate on how you solved this?
https://github.com/mleibman/SlickGrid/wiki
"SlickGrid utilizes virtual rendering to enable you to easily work with hundreds of thousands of items without any drop in performance. In fact, there is no difference in performance between working with a grid with 10 rows versus a 100’000 rows."
Some highlights:
Adaptive virtual scrolling (handle hundreds of thousands of rows)
Extremely fast rendering speed
Background post-rendering for richer cells
Configurable & customizable
Full keyboard navigation
Column resize/reorder/show/hide
Column autosizing & force-fit
Pluggable cell formatters & editors
Support for editing and creating new rows."
by mleibman
It's free (MIT license).
It uses jQuery.
The best Grids in my opinion are below:
Flexigrid: http://flexigrid.info/
jQuery Grid: http://www.trirand.com/blog/
jqGridView: http://plugins.jquery.com/project/jqGridView
jqxGrid: https://www.jqwidgets.com/
Ingrid: http://reconstrukt.com/ingrid/
SlickGrid http://github.com/mleibman/SlickGrid
DataTables http://www.datatables.net/index
ShieldUI http://demos.shieldui.com/web/grid-virtualization/performance-1mil-rows
Smart.Grid https://www.htmlelements.com/demos/grid/overview/
My best 3 options are jqGrid, jqxGrid and DataTables. They can work with thousands of rows and support virtualization.
I don't mean to start a flame war, but assuming your researchers are human, you don't know them as well as you think. Just because they have petabytes of data doesn't make them capable of viewing even millions of records in any meaningful way. They might say they want to see millions of records, but that's just silly. Have your smartest researchers do some basic math: Assume they spend 1 second viewing each record. At that rate, it will take 1000000 seconds, which works out to more than six weeks (of 40 hour work-weeks with no breaks for food or lavatory).
Do they (or you) seriously think one person (the one looking at the grid) can muster that kind of concentration? Are they really getting much done in that 1 second, or are they (more likely) filtering out the stuff the don't want? I suspect that after viewing a "reasonably-sized" subset, they could describe a filter to you that would automatically filter out those records.
As paxdiablo and Sleeper Smith and Lasse V Karlsen also implied, you (and they) have not thought through the requirements. On the up side, now that you've found SlickGrid, I'm sure the need for those filters became immediately obvious.
I can say with pretty good certainty that you seriously do not need to show millions of rows of data to the user.
There is no user in the world that will be able to comprehend or manage that data set so even if you technically manage to pull it off, you won't solve any known problem for that user.
Instead I would focus on why the user wants to see the data. The user does not want to see the data just to see the data, there is usually a question being asked. If you focus on answering those questions instead, then you would be much closer to something that solves an actual problem.
I recommend the Ext JS Grid with the Buffered View feature.
http://www.extjs.com/deploy/dev/examples/grid/buffer.html
(Disclaimer: I am the author of w2ui)
I have recently written an article on how to implement JavaScript grid with 1 million records (http://w2ui.com/web/blog/7/JavaScript-Grid-with-One-Million-Records). I discovered that ultimately there are 3 restrictions that prevent from taking it highter:
Height of the div has a limit (can be overcome by virtual scrolling)
Operations such as sort and search start being slow after 1 million records or so
RAM is limited because data is stored in JavaScript array
I have tested the grid with 1 million records (except IE) and it performs well. See article for demos and examples.
dojox.grid.DataGrid offers a JS abstraction for data so you can hook it up to various backends with provided dojo.data stores or write your own. You'll obviously need one that supports random access for this many records. DataGrid also provides full accessibility.
Edit so here's a link to Matthew Russell's article that should provide the example you need, viewing millions of records with dojox.grid. Note that it uses the old version of the grid, but the concepts are the same, there were just some incompatible API improvements.
Oh, and it's totally free open source.
I used jQuery Grid Plugin, it was nice.
Demos
Here are a couple of optimizations you can apply you speed up things. Just thinking out loud.
Since the number of rows can be in the millions, you will want a caching system just for the JSON data from the server. I can't imagine anybody wanting to download all X million items, but if they did, it would be a problem. This little test on Chrome for an array on 20M+ integers crashes on my machine constantly.
var data = [];
for(var i = 0; i < 20000000; i++) {
data.push(i);
}
console.log(data.length);​
You could use LRU or some other caching algorithm and have an upper bound on how much data you're willing to cache.
For the table cells themselves, I think constructing/destroying DOM nodes can be expensive. Instead, you could just pre-define X number of cells, and whenever the user scrolls to a new position, inject the JSON data into these cells. The scrollbar would virtually have no direct relationship to how much space (height) is required to represent the entire dataset. You could arbitrarily set the table container's height, say 5000px, and map that to the total number of rows. For example, if the containers height is 5000px and there are a total of 10M rows, then the starting row ≈ (scroll.top/5000) * 10M where scroll.top represents the scroll distance from the top of the container. Small demo here.
To detect when to request more data, ideally an object should act as a mediator that listens to scroll events. This object keeps track of how fast the user is scrolling, and when it looks like the user is slowing down or has completely stopped, makes a data request for the corresponding rows. Retrieving data in this fashion means your data is going to be fragmented, so the cache should be designed with that in mind.
Also the browser limits on maximum outgoing connections can play an important part. A user may scroll to a certain position which will fire an AJAX request, but before that finishes the user can scroll to some other portion. If the server is not responsive enough the requests would get queued up and the application will look unresponsive. You could use a request manager through which all requests are routed, and it can cancel pending requests to make space.
I know it's an old question but still.. There is also dhtmlxGrid that can handle millions of rows. There is a demo with 50,000 rows but the number of rows that can be loaded/processed in grid is unlimited.
Disclaimer: I'm from DHTMLX team.
I suggest you read this
http://www.sitepen.com/blog/2008/11/21/effective-use-of-jsonreststore-referencing-lazy-loading-and-more/
Disclaimer: i heavily use YUI DataTable without no headache for a long time. It is powerful and stable. For your needs, you can use a ScrollingDataTable wich suports
x-scrolling
y-scrolling
xy-scrolling
A powerful Event mechanism
For what you need, i think you want is a tableScrollEvent. Its API says
Fired when a fixed scrolling DataTable has a scroll.
As each DataTable uses a DataSource, you can monitoring its data through tableScrollEvent along with render loop size in order to populate your ScrollingDataTable according to your needs.
Render loop size says
In cases where your DataTable needs to display the entirety of a very large set of data, the renderLoopSize config can help manage browser DOM rendering so that the UI thread does not get locked up on very large tables. Any value greater than 0 will cause the DOM rendering to be executed in setTimeout() chains that render the specified number of rows in each loop. The ideal value should be determined per implementation since there are no hard and fast rules, only general guidelines:
By default renderLoopSize is 0, so all rows are rendered in a single loop. A renderLoopSize > 0 adds overhead so use thoughtfully.
If your set of data is large enough (number of rows X number of Columns X formatting complexity) that users experience latency in the visual rendering and/or it causes the script to hang, consider setting a renderLoopSize.
A renderLoopSize under 50 probably isn't worth it. A renderLoopSize > 100 is probably better.
A data set is probably not considered large enough unless it has hundreds and hundreds of rows.
Having a renderLoopSize > 0 and < total rows does cause the table to be rendered in one loop (same as renderLoopSize = 0) but it also triggers functionality such as post-render row striping to be handled from a separate setTimeout thread.
For instance
// Render 100 rows per loop
var dt = new YAHOO.widget.DataTable(<WHICH_DIV_WILL_STORE_YOUR_DATATABLE>, <HOW YOUR_TABLE_IS STRUCTURED>, <WHERE_DOES_THE_DATA_COME_FROM>, {
renderLoopSize:100
});
<WHERE_DOES_THE_DATA_COME_FROM> is just a single DataSource. It can be a JSON, JSFunction, XML and even a single HTML element
Here you can see a Simple tutorial, provided by me. Be aware no other DATA_TABLE pluglin supports single and dual click at the same time. YUI DataTable allows you. And more, you can use it even with JQuery without no headache
Some examples, you can see
List item
Feel free to question about anything else you want about YUI DataTable.
regards,
I kind of fail to see the point, for jqGrid you can use the virtual scrolling functionality:
http://www.trirand.net/aspnetmvc/grid/performancevirtualscrolling
but then again, millions of rows with filtering can be done:
http://www.trirand.net/aspnetmvc/grid/performancelinq
I really fail to see the point of "as if there are no pages" though, I mean... there is no way to display 1,000,000 rows at once in the browser - this is 10MB of HTML raw, I kind of fail to see why users would not want to see the pages.
Anyway...
best approach i could think of is by loading the chunk of data in json format for every scroll or some limit before the scrolling ends. json can be easily converted to objects and hence table rows can be constructed easily unobtrusively
I would highly recommend Open rico.
It is difficult to implement in the the beginning, but once you grab it you will never look back.
I know this question is a few years old, but jqgrid now supports virtual scrolling:
http://www.trirand.com/blog/phpjqgrid/examples/paging/scrollbar/default.php
but with pagination disabled
I suggest sigma grid, sigma grid has embed paging features which could support millions of rows. And also, you may need a remote paging to do it.
see the demo
http://www.sigmawidgets.com/products/sigma_grid2/demos/example_master_details.html
Take a look at dGrid:
https://dgrid.io/
I agree that users will NEVER, EVER need to view millions of rows of data all at once, but dGrid can display them quickly (a screenful at a time).
Don't boil the ocean to make a cup of tea.

jstree performance issues

I am using a jsTree with around 1500 nodes, nested to a max of 4 levels (most are only 1 level deep), and I'm getting Internet Explorer's "this script is running slowly" error. I began with just a straight html_data <li> structure, generated by ASP.NET. The tree wouldn't finish loading at all. Then I tried xml_data and json_data, which was a little better but eventually errored out. My last-stitch effort was async loading. This fixed the initial load problem, but now I get IE's error when I expand one of the larger branches.
More details: I'm using the checkbox plugin, and I will also need the ability to search. Unfortunately, when searching, the user could potentially enter as little as one character so I'm looking at some large set of search results.
Has anybody done something similar with such a large data set? Any suggestions on speeding up the jsTree? Or, am I better off exploring other options for my GUI?
I realize I haven't posted any code, but any general techniques/gotcha's are welcome.
I haven't completely solved my problem, but I made some improvements so that I think it might be usable (I am still testing). I thought it could be useful for other people:
First, I was using jsTree in a jQuery dialog, but that seems to hurt performance. If possible, don't mix large jsTrees and Dialogs.
Lazy loading is definitely the way to go with large trees. I tried json_data and xml_data, and they were both easy to implement. They seem to perform about the the same, but that's just based on basic observation.
Last, I implemented a poor man's paging. In my server-side JSON request handler, if a node has more than X children, I simply split into many nodes each having a portion of those children. For instance, if node X has say 1000 children, I gave X child nodes X1, X2, X3,..., X10 where X1 has children first 100 children, X2 has next 100 children and so on. This may not make sense for some people since you're modifying the tree structure, but I think it will work for me.
jsTree supports all your needs
use json_data plugin with ajax support where the brach would be too big.
search plugin support ajax call too
I'm a bit disappointed in it's performance myself.
Sounds like you need to try lazy loading: instead of loading the whole tree all at once, only load as needed.
That is, initially load only the trunk of the tree (so all nodes are "closed"), then only load a node's children when user clicks to open it.
JsTree can do this, see the documentation.
(Is that you mean by "async loading"?)
jstree sucks - it is the "refresh" which is slow 10 seconds for a 1000 child nodes being added, or to load a tree with 10000 items among 40 nodes it takes over a minute. after days of development I have told my colleague to look at slickgrid instead, as everyone will refuse to use a page which takes so long to do anything. it is quicker if you do not structure it correctly eg 3 seconds for 1000 nodes but then the arrow will not have any effect to close it down.
This is to replace a combination of ms treeview and ms imagelist which loads the same 10000 items across forty parent nodes in 3 seconds.

how to handle large dataset like sproutcore

I really don't have any substantial code to show here, actually, that's kinda why I am writing: I looked at the SproutCore demo, especially the Collection demo, on http://demo.sproutcore.com/sample_controls/, and am amazed by its loading 200,000 records to the page so easily. I tried using Rails to provide 200,000 records and in a completely blank HTML page with
<% #projects.each do |p| %>
<%= p.title %>
<% end %>
that freezes the browser for seconds on my m1530 laptop with 4gb ram and t7700 256gb ssd.
Yet the sproutcore demo does not freeze and takes less than 3 seconds to load.
What do you think the one technique they are using to enable this is?
Thanks!
The technology that SproutCore uses to display and scroll smoothly through "infinite" lists of data has very little to do with where the data comes from and almost all to do with the integration of special SproutCore view classes, SC.CollectionView (the parent class of SC.ListView and SC.GridView) and SC.ScrollView; the collection of powerful client side datastore classes: SC.Store and SC.SparseArray; and the SproutCore runtime and controller architecture.
The fact is that you simply cannot render a list of several hundred thousand items in it and expect the browser not to grind to a halt. That is too many elements to insert into the DOM tree and that is why SC.CollectionView is optimized to only generate elements for the currently showing items in the list (ex. if only 20 items are visible out of 20 million, only 20 elements are in the DOM). It gets even better than that though, because by default as items scroll in and out of view, the few existing elements are updated in place with the new item information so that the DOM tree is not even touched. This would not be possible though without the integration of SC.ScrollView that allows the collection to be aware of its visible rect and when a scroll is about to happen.
On top of that, there is the entire SproutCore runtime architecture which is used to ensure that all DOM manipulations are queued up so that you only touch the DOM once per run loop if needed when a display property changes (ex. toggling a display property 50 times in one run loop only touches the DOM once with the final value). This is an important factor in extreme performance that affects all SproutCore views including SC.CollectionView.
Finally, to make the list really scream, you cannot load several million items into the client in one request, nor can you even store them all in client memory. This leads me to another optimization of SC.CollectionView and the SproutCore data store, which is to work with sparse data. SC.CollectionView will never try to iterate over every item in its content, so it doesn't need all the data present, only what is being shown. When we load data into the client, we would use an SC.SparseArray to page in a bit of data at a time as needed. The whole system is very elegantly designed so that when the collection view requests an item that the sparse array doesn't yet have, the sparse array fetches it (or the next page of items) in the background. Because of bindings and observers, when the new data comes in we can update the list in place, which means that the scrolling doesn't block while data is being brought in.
That demo above is very outdated, here is a new one that uses the technologies I mentioned above: http://showcase.sproutcore.com/#demos/Big%20Data (source is here: https://github.com/sproutcore/demos/tree/master/apps/big_data). In this demo, I scroll through 50,000 names, which is all I could generate and split into 500 JSON files of a 100 names each that are loaded remotely from the server. Once you scroll past 100 names, you will see that the next 100 names are paged in and there is a brief flash of placeholder text "…" (how long you see the placeholder text depends on your Internet connection).
I used 50,000 names, but I don't see any problem showing a list of 500,000 or 5 million names though. However, at that scale you would want to also 'un-page' data as you bring in new data using SC.Store#unloadRecords to keep the memory use down.
There's a few other technologies in play to make this whole thing possible that I've missed, but those are the main ones at least.
I imagine the demo provided isn't being generated dynamically - it's static data.
Very few systems would be able to iterate a collection of live data that size. There are a number of techniques including streaming the dataset (using batch iteration through the records) through to caching and ajax partial loading strategies.
More on sproutcore here.. http://ostatic.com/blog/sproutcore-raises-the-bar-for-client-side-programming
If on the other hand you are looking for concurrency then node.js is the way to go.

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