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Asked: 2026-06-08T00:48:02+00:00

I couldn’t really word the question less vaguely, but I think you will understand…

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I couldn’t really word the question less vaguely, but I think you will understand…

I am developing a game engine in Javascript, and the Scene object, which is a container of many things, has a method that is supposed to change one array in it, specifically the one holding all the things that can be drawn.

This array is accessed like this:

scene.internals.draw

The problem is, it is referenced many times in the method, and I think that the name/path might change. Naturally, I don’t want to change every reference to it in the method each time I change the the array’s path, so I did this:

var location = scene.internals.draw;

Now, the actual method code and the algorithm can stay intact, and if the name/path of the array in the scene changes, I only need to change that one line.

And it works pretty well for the most part. I can .push(obj) to it, etc, but at one point, I need to “disect” the array, ie, split it in half, add something, and then put it back together, like this:

buff1 = location.slice(0, i); //First slice of the array.
buff2 = location.slice(i, location.length); //Second slice of the array.

//Add something in between those slices.
buff1.push(ob);
location = buff1.concat(buff2); //Problems here!

This worked well while location was just scene.internals.draw, as it changed the array directly. But now, I assign the new value to the local location variable, not the desired scene.internals.draw one!

Question: how can I, using the = operator, assign values to “real” objects, instead of the variables that contain references to these objects (like location)?

The obvious solution would be this, at the end of the method:

scene.internals.draw = location.slice();

This is OK, the only side effect is that I will have to write the original name twice, and edit it twice, which isn’t such a big issue. But, I maybe find myself in other situations where I just might need that functionality, so I’d still like an answer.

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1 Answer

  1. Editorial Team

    There is no assignment by reference in javascript, so you cannot do this. What you are doing is usually mistaken for assignment by reference but it is in fact a copy of a reference value which has implications like this.

    You probably have a deeper problem somewhere since you are doing this but I don’t wanna get into that.

    You could do this:

    location.splice( 0, location.length ); //Remove all items in the array
location.push.apply( location, buff1.concat(buff2) ); //Push the buffers into the array
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