Develop Reference

Aurelia JS - multi level binding/update?

I'm not sure whether I'm using the right terminology here - but here is an example:
https://gist.run/?id=57ed46429e4583eb4c3fb11814451a55
This is how it looks like in Chromium:
Basically, the entries on top (red outline) are a visualization of an array as the "first-level" data display; here one can toggle each element's selection, and make a multi-element selection (red background). The array that is the source of the "first-level" display is mydata in first-level-items.js.
Those items that are selected in "first-level", are then shown again in "second-level" (green outline); here the same information of name and value is displayed, although a bit differently. Here also one can toggle an elements selection - but only one "second-level" element can be selected. The array that is the source of the "second-level" display is myseldata in second-level-items.js.
The intent here, is that once a "second-level" selection has been made, a slider appears, to change the .value property of the particular object which is the selected array element.
My original question (which is why I started this post/example at all), was:
How do I ensure that whenever the slider is changed, the value is updated in both second-level and first-level display?
... however, for reasons beyond me, this in fact does work somewhat in this gist.run example (but it still doesn't work in my actual project, which forced me to come up with the example to begin with). Also it only works somewhat, in the sense that when loading the example page at first, after making first and second level selections, and then changing the slider, the .value will be updated in both first- and second-level display. But as soon as I try deselecting on second level - or changing the selection on second level - then updating stops. So, I guess this question still stands...
After a second-level selection has been made, deselecting on second level (by clicking to toggle) does NOT remove the slider; how can I have it behave like that?
The update happens only on the slider's onChange - basically, while you drag and slide, this component emits onSlide, but it will generate onChange only at the end when the mouse is released (that is, when the sliding has stopped). How can I update both first- and second- level display while the slider is sliding?
And finally - is this how this kind of a problem is best addressed in Aurelia? That is - I currently have one array in first-level-items.js; first-level-items.js then has a singleton reference to second-level-items.js, so it can call a method within it, to change a filtered copy of the array on the second level, which then serves as a source both for second-level display and the slider... Is there a better way to organise this?

Boy, this was a pain, but here's what I think is the solution:
https://gist.run/?id=c09fea3b82a9ebc41e0a4c90e8665b04
Here are some notes:
Apparently, there is something wrong applying if.bind or show.bind on the input element of the slider - instead, the input element should be put in an enclosing div, and the div should have if/show.bind applied
Furthermore, if.bind should not be used, as it re-instantiates the slider element - use show.bind so we can get a reference to the slider widget at start already, even if it is hidden
Seemingly, using TaskQueue in attached() is the only way to get a reference to the slider at start
Once we have a reference to the widget, re-apply it on each second level element, whenever they change
Do not set this.myselChanging to null to specify no target of the slider (simply count on hiding the slider appropriately)
For a continuous change (onSlide), simply use this.myselChanging.value = e.value; in the handler - both first-level and second-level values will be changed
Beyond this, it seems arrays are copied by reference, so the multi-level update happens without further intervention...
Though, would still love to know what is the proper way to do this...

Highlight last inserted document in Meteor

I have form and list of objects at the same page. When I insert a new row, it is not very easy to see where the newly inserted row is placed. Therefore, I thought I could color/highlight the newly inserted row (and perhaps remove the highlight after a few seconds).
How can I do this? I think a way to do this could be using a method on the server which returns the inserted id (return Collection.insert(doc);) and on the client use a callback with
Meteor.call('insertDoc', function(err,result) {
// do something with result
});
I think I can use a reactive-var to save the id of the last inserted row and in the loop highlight the row with
{{#each docs}}
<li class="{{isActive}}">{{name}}</li>
{{/each}}
and have a helper to return active if this._id equals the reactive var with the last inserted id.
But is this the best way to do it? How can I remove the color after some seconds? I have seen such behaviour on many pages but I cannot find any tutorials/code snippets to achieve this.

I wrote a package that uses Meteor's UI hooks to fade items in and out of a list as they are added and removed, to help users maintain context as data changes:
https://github.com/mizzao/meteor-animated-each
There is a demo at http://animated-each.meteor.com/. You can see that as items are added and removed, they are faded in and out. If items are inserted off the screen, the visible area does not scroll.
This isn't doing exactly what you want, but you can use the same idea to highlight items as they appear as well, as opposed to the simple fade in.
Note that all of this happens at the UI rendering level - not the template/code level. The UI hooks are also not well documented right now, but they've been around for a while.

I don't know if your method is the best, but that's how I'd go about doing it.
As for the animation, I'd use a CSS3 animation. Plenty to choose from ( https://developer.mozilla.org/en-US/docs/Web/CSS/animation ), and you can easily make them fade to the standard color. The animation would also only be applied to the last inserted item (because of the way you did it, only the last item would have the "active" class)

Sortable.js is not working: List items are not draggable

I have tried a very simple example with Sortable.js: Two lists: One is currently empty, and will store item copies from the other list (which is static).
I tried defining pull and put values for each list, defining the same group name, but it does not work. In fact the static elements from the filled list are not draggable at all.
I have written the example at JSbin. Since I am new to JS, I accept all kind of constructive comments.
BTW: any way of drawing the bootstrap list borders even when empty?

I have edited the jsbin and did the following corrections
Replaced the sortable.js with
<script src="//cdn.jsdelivr.net/sortable/latest/Sortable.min.js"></s‌​cript>
You were accessing the ids with _ (instances_list, main_list) whereas the ids were having an -
For the appending to work I had to add one item by default to instances-list than keeping it empty
JSBin

Paper.js - Get first ''selected item'' from selectedItems

I'm trying my way around building a graphics editor with Paper.js
I would like to select the first(1st) element that was picked using a selection tool(either Shift+Click, or dragging a selection box). Direct-click detection is done via hit-testing and selection box via getIntersection
If it's Shift+Click its the first selected element. Which element was clicked is found with HitResult
If its selectionBox, the first intersection? result of the selection box.
Is it possible to get this?
I do a FOR loop to get all the elements in the Paper.js selectedItems array which returns all the selected items on the canvas.
I've tried this:
var selected = paper.project.selectedItems;
var firstSelected = selected[0];
but this doesn't return what i need.
The above code snippet fetches an array that is agnostic to which element was selected first. It simply orders the selectedItems in the array starting from the ''oldest drawn path''.
What i need is a way to find out which is the 1st element that was selected.
Either the 1st that get's ''touched(intersected)'' with the selection
rectangle
Or the first that was clicked while in Shift+Click
functionality(Select more than one element with click).
The reason for this is that i would like to add to my editor, align-relative-to functionality.
In order to have a correct UX, the user must have the ability to align an element relative to another that he sets as the ''reference item''. Therefore i need to know the 1st element selected relative to others in order to use it as the ''reference item''.
Any ideas ?

Here is a working example of what I understood you want to achieve for the selection (without the align-relative-to functionality).
And here is the code (under SelectPaperJS) https://c9.io/arthursw/oiio/
It should not be too hard to make something similar on Stylii (since you're using it).
You can have an array to keep track of the order of selection of your items. For example in the mousedown function of the direct select tool (from line 789 of editor.js) you can add the newly selected element to this array (line 800). Same thing when you select with the rectangular selection tool.

Manipulating jQuery draggables/droppables in script [UPD]

I want to append item to sortable list by script. Users can drag item to list directly, and can check some checkboxes and press "Send to list" button. First approach works, second is not.
The problem is if I pass $(ui.draggable) to function, it works. But if i point to draggable element by jQuery chain ($(this).parent().parent().find('div.drag')) and pass this, it won't work. It seems that these two objects are not equal (i tried cloning second object and reducing it to one with eq, and nothing works).

Okay, i got it :) Problem was in move_to_list function.