npm to create a package.json file out of the package-lock.json file?

The package-lock.json does not contain enough information to produce an accurate package.json file. It contains a list of all the package that are installed, and the version, but it also includes sub-dependencies in the list.

You could read the information and create a new dependencies list, but you would end up with a list of all the dependencies, including sub-dependencies you don't directly depend on. There would also be no distinction between dependencies and devDependencies.

Interestingly, npm does seem to be able to remember which packages were installed in a given directory for some amount of time (it's probably cached somewhere). If the lock file was originally created on your machine, a simple npm init might give you an accurate package.json file.

If you really want to produce a list of all the packages in a JSON format, you could use a script like this:

var dependencies = require('./package-lock.json').dependencies; var list = {}; for (var p of Object.keys(dependencies)) { list[p] = dependencies[p].version; } console.log(JSON.stringify(list, null, ' '));