npm pack and missing package-lock.json

Question

from npm documentation:

By default, the following paths and files are ignored, so there’s no need to add them to .npmignore explicitly:

.*.swp
._*
.DS_Store
.git
.hg
.npmrc
.lock-wscript
.svn
.wafpickle-*
config.gypi
CVS
npm-debug.log

Additionally, everything in node_modules is ignored, except for bundled dependencies. npm automatically handles this for you, so don’t bother adding node_modules to .npmignore.

when npm pack is executed, package-lock.json is not included in the archive.

is it a bug or is it expected and undocumented behavior?

Answer 1

from package-lock.json docs:

One key detail about package-lock.json is that it cannot be published, and it will be ignored if found in any place other than the toplevel package.