Failed to read dependency... must specify a version

Greetings!

I’m trying to install the mailgun.js package and am getting this error at one of its dependencies, “web-streams-polyfill”, which is comprised of smaller polyfill packages for es6, es2018, ponyfill, etc.—each of which do not specify a version in package.json.

I’ve tried to add a version by hand in each but when I upload my node_modules.tar.gz and run a function, no dependencies can be found (e.g. ‘Cannot find module “mailgun.js”’), even those which I had working before this.

MailGun is a popular service. Surely I can’t be the first to run into this.

Many thanks for reading—any help is greatly appreciated.