Node zlib crazy memory consumption

Question

I'm writing a script that appends JSON to a write stream using Node's archiver package. archiver then tarballs and gzips the write stream to a local file on disk.

When I run this script however, the process' memory consumption can get up to 2GB! Without using the gzip: true flag in archiver (that is, just using archiver to append to stream and tar), the script only uses 300MB of memory.

I worked around this by spawning a child process to gzip the tarball, but I'd love to know two things:

1. Why is archiver and by extension, zlib, moving the whole tarball to memory for compression?
2. Is there a way to work around this without exec-ing to the shell?

Thanks!