Memory leak in instance arrays

[melgrove]

There is a pretty large memory leak when adding multiple instances of Points, Shapes, or Lines.

Reproduce

1. When points(), shapes(), or lines() is called, it adds a Points, Shapes, or Lines instance to the global pointsInstances, shapesInstances, or linesInstances array. Each instance contains all of the layer information.
2. When .remove() is called on one the instances (for example: let pointLayer = glify.points({...}); pointLayer.remove()), the instance is not removed from the global instances array. This causes a very large memory leak when rendering and rerendering points many times, since the entire object for every render stays in memory after it has been removed.

A solution

My application must be able to rerender many points many times so I created a workaround. I think that this could be added to the .remove() method, unless I'm missing something.

1. Store an ID with the instance when creating it:

   let pointLayer = glify.points({...});
   const savedID = generateUniqueID(); // just needs to be unique across the instances
   pointLayer.layerID = savedID;
   

2. When .remove()ing the instance, also remove it from the instance array manually:

   const instanceIndex = glify.pointsInstances.map(inst => inst.layerID == savedID ? true : false).indexOf(true);
   glify.pointsInstances.splice(instanceIndex, 1);
   

[melgrove]

It doesn't look like there have been any updates to the package since I created this issue so I don't think so, unless you are referring to something else. I'm probably going to PR a fix and add it to my fork