The need to manually dispose() meshes, geometries, materials, and textures is quite annoying, and according to this stackexchange comment, is a concequence of the lack of WeakMaps in javascript. Now ...
This is a fast, lightweight (~1.94kb ungzipped, and only 703 bytes gziped) JavaScript Map and Weakmap polyfill. If you don't want to download the script, then you can ...