pnpm fatally errors when a package contains a whitespace-only license field.

[Tellan]

pnpm version: 1.35.3

Code to reproduce the issue:

https://gist.github.com/Tellan/e76e9f58acc7afb71fe67368772de1d8

Expected behavior:

pnpm install should successfully complete.

Actual behavior:

pnpm install throws because of the empty license field.

Additional information:

• node -v prints: v9.3.0
• Windows, OS X, or Linux?: Linux

npm handles this situation just fine, but pnpm exits with an error. I tracked the error down to these lines in normalize-package-data which fails to check for a whitespace string before passing it to the spdx parser.

[zkochan]

Can you publish such package to the npm registry?

[Tellan]

It errors even when calling pnpm install in a package directory with an empty license, but here's a package anyway:

https://www.npmjs.com/package/pnpm-license-test

[zkochan]

Seems to work as of v2.25.2