How do I find and remove objects in an array?

[d.healey]

@VirtualVirgin The problem is each time you write {} you are creating a new object. So in your indexOf and remove functions you are creating new objects.

Instead you need to reuse existing instances of those objects.

const obj1 = {a: 1, b: 2};
const obj2 = {c: 3, d: 4};

const arr = [obj1, obj2];

Console.print(arr.indexOf(obj2)); // 1

[VirtualVirgin]

@d-healey
Yikes! I have a mess then. I have to name every object inside the array by declaring a variable for it?

[d.healey]

@VirtualVirgin said in How do I find and remove objects in an array?:

I have to name every object inside the array by declaring a variable for it?

Nope. That's just the way of explaining why you were having the issue you described. There are more practical ways to do this kind of thing but the best approach will depend on exactly what you need to do and the context in which you're doing it. I need more info.

[VirtualVirgin]

@d-healey I'm working on a primitive piano roll for MIDI note editing and having trouble with note selection.
To try this out, just double-click on an empty cell to create a note, and double-click again to destroy it.
I think I fixed the adding and removing of array objects.

What I am working on now is trying to get the selection methods to work properly for each condition. If I select a note by clicking, that is working, but my click-drag selection is not (even though I can see it is populating my "selectedNotes" array properly).

The issue seems to be with my "isSelected" inline function, which is working for the click selection, but not the drag selection.

After that, I need to fix the selection drag to move the notes, as it was working but I broke it somehow.

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[d.healey]

@VirtualVirgin said in How do I find and remove objects in an array?:

I'm working on a primitive piano roll

Have you seen the built in piano roll with the MIDI player? I think it might just be a viewer, I haven't played around with it. Lots of docs though.

[VirtualVirgin]

@d-healey I did take a look at it, but I don't see any way to edit the notes from the viewer. I just think it outputs the graphics from a MIDI file, so I though it was just as well if I try to build my own.

[d.healey]

@VirtualVirgin Yeah I think you're right about the viewer. But you can use the player as the backend to manage the tracks, notes, etc. and build your own UI to display and edit.

[d.healey]

For the original problem you might be able to make use of some of the fancier array functions like map, filter, find, some, etc. Or just use a good ol' fashioned loop to manually search the array for the object you're interested in.

[VirtualVirgin]

@d-healey said in How do I find and remove objects in an array?:

For the original problem you might be able to make use of some of the fancier array functions like map, filter, find, some, etc. Or just use a good ol' fashioned loop to manually search the array for the object you're interested in.

I am using filter and map in this script, but I am new to them so I may not be using them correctly.

My trouble at the moment is detecting which notes are selected

"selectedNotes" is an array that is getting populated properly to tell me which noteCells are selected,
but then I run this inline function to check and this only works somethimes:

// check for selected notes
inline function isSelected(cell)
{
	local sRow = selectedNotes.some(obj => obj.row === cell.row);
	local sCol = selectedNotes.some(obj => obj.col === cell.col);
	if (sRow && sCol)
		return true;
	else
		return false;
};

I am trying to use that like "array.contains()", but in this case for specific objects ("cell").
The "cell" is an object with the coordinates i.e. {"row" : 60, "col" : 4}
This works when I use click or shift click to select my notes, but not when a drag selection has been made. Not sure why as they both populate the selectedNotes array.

[d.healey]

@VirtualVirgin For those functions (some, filter, etc.) the first parameter should be a function.

Edit: I just realised you're doing the javascript arrow function thing, we don't have that in HISE.

[VirtualVirgin]

@d-healey said in How do I find and remove objects in an array?:

@VirtualVirgin For those functions (some, filter, etc.) the first parameter should be a function.

Edit: I just realised you're doing the javascript arrow function thing, we don't have that in HISE.

No, the arrow function definitely works:

[d.healey]

@VirtualVirgin

Oh that's good to know, thanks!

Now I can do this kind of thing:

Engine.showYesNoWindow("A title", "Some text", response => {
	Console.print(response);
});

You could replace this

	if (sRow && sCol)
		return true;
	else
		return false;

With return sRow && sCol

But this doesn't solve your issue. Can you make a simple snippet that demonstrates the issue?

[VirtualVirgin]

@d-healey
I found where the problem is taking place:

            selectedNotes.push
            (
	            selectedNotes.filter(function (c) 
	            {
	                var cx = c.col * cellWidth;
	                var cy = height - (c.row + 1) * cellHeight;
	
	                return 
	                (
	                    cx + cellWidth > x1 &&
	                    cx < x2 &&
	                    cy + cellHeight > y1 &&
	                    cy < y2
	                );
	            })
            );

This selectedNotes.push is pushing an object inside an array to the selectedNotes array, whereas I only need it to push an object to the array.
So the current result is looking like [[{"row":42, "col":4}]]
but I need it to just look like [{"row":42, "col":4}]
I am not sure how I modify that to just use a the object and not have it wrapped in that extra array.

[d.healey]

@VirtualVirgin Add [0] after the parenthesis

[VirtualVirgin]

@d-healey Almost...
that turns it into an object, but it only returns one selection to the list instead of all of the noteCells under the selection rectangle area.
Without the [0] it returns all of them, but inside an array.

[d.healey]

@VirtualVirgin In that case after it returns them, just grab the [0] element from that array.

[VirtualVirgin]

@d-healey Whoops... is there a panic button of some sort for feedback loops? I got stuck in one.

[d.healey]

@VirtualVirgin What do you mean?

[VirtualVirgin]

@d-healey I added a for loop after that function and it seems to be stuck in the loop

[d.healey]

@VirtualVirgin What does the loop do?