The Angular Datagrid. Highly optimized AngularJS datagrid. Easily modify and add your own behavior with addons! Now your ng-repeat doesn't have to bog down your app when you have lots of data to show.
Author: 5250952? webux
Submitted by: 4192463?v=2 Joebob12


ux-datagrid : An Angular DataGrid

Highly performant list and datagrid for AngularJS designed for mobile devices which just makes it all the better on a desktop.

Most lists work with recycled or just in time created rows for long lists in angular. Datagrid doesn't work that way because in order to get a smooth scrolling experience on a mobile device you need to allow the browser to handle the scrolling as much as possible. So to accomplish this Datagrid works on a chunking algorithm to create pieces as they come into view, but never destroy them until the whole grid is destroyed. This allows the scrolling experience to be smooth because GPU is leveraged from the browser as the dom is considered to be static until in view.

Of course since this is angular there is then the issue with a digest being too expensive. This is not a problem because all rows are disabled from the digest when out of view and enabled when in view. So they don't loose their scopes or have to create new ones constantly, but only once. Then they are just enabled or disabled as they come into view.

More Examples

What makes this list/datagrid different?

Chunking is the concept of grouping the dom elements in hierarchies so that the browser does not calculate the position of every element when one changes, but only those in that container, it's parents in it's container, and so on up the chain. The smaller the groups the less the browser has to redraw, size, and position elements because it can just move the parent of necessary. This works regardless of rows all having the same heights or dynamic heights as long as there is a template for each different height.

Using this concept datagrid is able to create many more rows that are listed natively like static html and allows the browser to use GPU snapshots to keep scrolling smooth. Dynamic changes cause repaints that are expensive, so this avoids that.

Chunking doesn't have to create them all though. To make sure the datagrid could start up and jump to any section quickly it needed to be able to only put in chunks that are in view. So once a chunk is requested it will be created if it was not already. This makes it so that a list of 50,000 items can still start up quickly and jump to any location and scroll as smooth as glass on your mobile device.

Time to get your hands dirty!

Datagrid uses the concept of templates for your rows. You can have as many templates as you like. You can even overwrite the templateModel for one of your own as long as you implement the same API. You just need to assign it as an addon. (We will discuss those later).

First we will create the directive and assign it an array so it has something to display.

These items are read from the scope that the datagrid exists in. It will then take that data and convert it into a normalized array so it can display every item. This does nothing for single dimentional arrays, but for arrays that are multi-dimentional it creates a single array of those based on the grouped property.

Grouped property is for reading a hiearchy. If you have an object with the property children that is an array, then "children" would be your grouped property for the datagrid to read it. See this example for use of grouped data. Grouped Data Example

In most cases your datagrid will look similar to this one below.

What is really happening here is that the directive is setup with a script template inside of it. The script template allows the contents of it to be read as a string rather than be interpreted as dom by the browser. So it makes a very convenient way of writing out your row templates.

The script template has 3 properties.

  • type="template/html" it uses this to match on. So if you don't get it right might not work. This is required.
  • template-name if this is not defined it will be changed to 'default'. So this one is not required if you only have one template, but if you have more than one the second will overwrite the first without this property.
  • template-item this is what you want the data to be referenced by on the row scope. Such as in angular if you do a repeat with "item in items" you then reference item in your template. This does the same thing with this property.

Dynamically specify your templates instead of using script templates

As of 0.6.4 you can also pass a template data object to be used an an option to script templates. To do this you just need to reference an object and pass to the grid options like so.

Then just define "tempalates" on your scope. Like so:

Please note that script templates will override these templates if they have the same name. Such as if you have a template with the name 'default' and a script template with the data-template-name="default" then the script template will overwrite the other template.

Addons / Plugins

Addons are like a plugin to the datagrid. It actually becomes a behavior modifier of the datagrid object. Addons are created as factories and applied directly to the datagrid instance. The internals of the datagrid are constructed with addons as well.

Because these addons assign themselves as behaviors to the instance behaviors can be overwritten. So if you need to modify core behavior then go right ahead and add an addon that overwrites those methods.

How to create an addon Addons are factories that modify the behavior. To create an addon you just need to create the factory and then add it to the dom.

Now we need to add it to the dom.

Now when this datagrid is created it will call the "datagridVersion" factory and pass to it the datagrid instance so that it can be modified.

Any public methods can be overwritten allowing you to change internal behavior. Not all methods are public, but hopefully the ones you need.

It is also handy to have addons that will update based on events. Here is an example of an addon that updates based off of some events that the datagrid will throw. For this example we will assume we are waiting for some data to load asynchronously through a service. So we want a spinner until the data is loaded.

Why use iScroll

I had my own version of a scroller. However, datagrid is not a scrolling solution, it is a long list rendering solution. Scrolling can be done with any javascript scrolling solution. IScroll is a popular scroller so I used it to leverage the reuse of other libraries with the addition of addons to make them compatible. Also notice that I only implemented this for the iOS. Android works well with native scrolling.

Without iScroll

I found that in some really long lists in a project that I was using the datagrid in that iScroll would crash in Safari on mobile devices. These lists were over 7k items and had very complex rows. However, I made an addition so that we have ux-datagrid-scrollBar.js now so you can make your app work without iScroll and avoid the memory leak. I am not sure if the memory leak is the fault of Safari or iScroll, but the combination of the two was crashing with an out of memory error on iOS devices. To use the scrollbar on iOS devices (Android 4.0 devices do not need an extra addon because they already handle much of the scrolling natively) you need to add to the options {scrollModel:{manual:true}}. This will enable touch events to cause the iOS devices to work with their native scroll and still be able to flick. And of course, don't forget to add the scrollBar addon in your addons.

No JQuery

AngularJS Datagrid doesn't have any JQuery dependencies. This helps to keep your application light weight.

options.chunks.detachDom mode

Some browsers cannot handle a large amount of dom in the page (Cough... IE). So to improve performance in those browsers I added the detachDom mode. It still renders the chunks, but will detach the ones out of view. The number passed to the detachDom mode is how many dom rows to render in each direction of the current visible area. So if your chunks were 10 rows per chunk and you wanted to have one chunk in either direction from the view area then you would set detachDom = 10. I have used this in other places to optimize browser responsiveness. Slower devices benefit from this as well.

Running Unit Tests Locally

You can run the unit tests and samples locally by running

inside of the app directory. Then starting the server.

Then you can just pull it up in your browser on "http://localhost:4000/".

About Addons

Addon: disableHoverWhileScrolling (desktop/ux-datagrid-disableHoverWhileScrolling.js)

This addon is used to do obviously what it says. This increases performance while scrolling because hover events if there are a lot on the page can affect performance.

Addon: focusManager (desktop/ux-datagrid-focusManager.js)

While this is listed under desktop, it actually has several uses for touch browsers as well. It has built in functionality to move next and prevous through rows selecting similar items.

So for example lets say you have an input in a row. Focus manager on focus would build a selector for that input. Then when you have a button that tells it go to to the next item. It will look up that next item based on the selector from the previous row. If the selector doesn't match it will skip that row. Making it jump over rows that might be headers and such. You can see an example of this in the example app under focus manager. If you are looking for more of a full focusManager for your whole app you should check out angular-ux-focusmanager.

To tell the focus manager to go to the next item you would need to get the datagrid instance from the scope. Let's add an example below of a controller with a datagrid.

Using the above html, and having a controller like the one below we could access the grid like this.

Here is a JSFiddle example of how to make your grid work like tables with columns. ux-angularjs-datagrid tables

Addon: Collapsible Groups (ux-datagrid-collapsibleGroups.js)

Collapsible groups it meant to work with grouped data. Given an array like the following.

Each Group has sub groups of list. In the template we pass the data-grouped="'list'" so that the datagrid knows which child property to normalize. The datagrid will convert the structure into a single array like the one below.

Then we have group "a" and group "b" that are now indexed and no longer actual groups. The collapseGroups addon will take this new structure and when a group is clicked it will hide all children from that group and update the heights accordingly. This will essentially hide all children of that group leaving the group header.

Addon: Expandable Groups (ux-datagrid-expandableGroups.js)

While this is easy to confuse with collapsible groups this addon performs very differently. it is optimized to remove rows instead of just hiding them like with collapsibleGroups. This has pros and cons to it.

While it will be able to do an expandAll and collapse all which the collapsibleGroups cannot do. It cannot change without reloading the data which means that you can see a flicker of the list. (This is if you are using the built in styles, if you take the transitions off then the flicker is unnoticable).

Addon: Expanded Rows (ux-datagrid-expandRows.js)

This one works in a similar way to collapsible groups. It changes the heights of rows to simulate an effect. In this case it makes the rows taller. Collapsible Groups actually changes their heights to 0 and makes them not display. Expand rows work with different templates. So you need to setup some options. Given the following grid, see the options.

Notice that expandRows option gives a template, and cls property. The template property is the name of the template to affect, and the cls is the css class that gets assigned to that row when it is expanded. Then with the css transitions can be done or just popped open as well. Transitions may suffer from chunks that do not transition as well so in my examples I have just had them snap open. All I needed to do is add a new height to that css class so that when it is added the row expands. The datagrid does the rest.

Addon: Grid Logger (ux-datagrid-gridLogger.js)

The grid logger is a way to display errors or other log data from the grid. It is set to listen to grid events and log those values. The datagrid doesn't log directly, it throws events for logs. Notice the options. Grid logger can capture events for all addons, or it can capture them for only items specified.

With debug:{all: 1} your going to get a lot of log data. With debug:{scrollModel:1} you just get events from the scroll model. So when building your addon this can be handy to debug your addon. You can also turn logs off. debug:{all:1, Flow:0} turns off the flow control logs, but loggs everything else. debug:{all:1, Flow:0, scrollModel: 0} turns off Flow and scrollModel, but logs the rest.

Addon: Infinite Scroll (ux-datagrid-infiniteScroll.js)

Infinite Scroll needs a couple of hooks to work. First your data to start, and then a method that will update the data when it reaches the bottom. This method can be asynchronous because the datagrid watches for it's data to change. So once the data changes in the array, it will update. The limit property can be helpful as well. With this it will tell the addon that it should not show the loading row once the limit has reached this value.

IE8 Compatibility

IE8 may work with ux-datagrid by adding some polyfills for emulating missing ES5 features in IE8. First it's required to add ES5 Shim and also an additional file Polyfill IE8, located in this repository from this repository.

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