change(utils): use Array.flat() in flatten()

[hobbitronics]

Changed

• use Array.prototype.flat() in utils.flatten

[davidaucoin7377]

Review

[mrmlnc]

LGTM.

[mrmlnc]

@jonschlinkert, you have a plan to remove support for older versions of node.js? The .flat method available starting with [email protected].

[jonschlinkert]

Yes, we can remove support for older versions. LGTM

[hobbitronics]

This might change your performance numbers mentioned in the README.

[jonschlinkert]

FWIW, while I'm always in favor of making improvements, the reason I don't generally like this kind of PR is that this is a zero-sum exchange at best. This will trigger thousands or potentially millions of cascading PRs for people to patch their libraries, and the aggregate manual effort and computes consumed in the process will almost certainly "cost" more than what you think is being saved by removing the dependency.