pdfjs-dist doesn't have core-js in dependencies

[AndreyChernykh]

Attach (recommended) or Link to PDF file here: N/A

Configuration:

• Web browser and its version: N/A
• Operating system and its version: Mac OS
• PDF.js version: Any
• Is a browser extension: No

Steps to reproduce the problem:

1. N/A

What is the expected behavior? (add screenshot)

pdfjs-dist should have all required 3rd-party packages (including core-js) explicitly specified in the package.json dependencies.

What went wrong? (add screenshot)

If in the app a version of core-js mismatch the implicit expectation of the pdfjs-dist code in pdfjs-dist/lib/shared/compatibility.js, then it leads to unexpected behaviour or build errors, such as

Module not found: Error: Can't resolve 'core-js/es/string/starts-with'

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):
N/A

See similar issue parcel-bundler/parcel#2819 (comment)

[AndreyChernykh]

@Snuffleupagus Hi

Sorry, I don't fully understand how is the linked PR related to the bug?

There are explicit core-js usages in pdfjs-dist
https://github.com/mozilla/pdfjs-dist/search?q=core-js&unscoped_q=core-js

And no explicit dependency from core-js, which means, that pdfjs-dist will use whatever version of core-js is happen to be used in the app.

[timvandermeij]

The pull request is making it more clear that the /lib folder shouldn't be used for anything other than unit tests. For using PDF.js you should use the pre-built versions because core-js is a dev dependency and its references will be resolved on build time. Hence there should be no need to put core-js in the dependencies of pdfjs-dist.

[AndreyChernykh]

@timvandermeij Got it! Thanks.