Add strict directive to cjs files for better performance

[Fdawgs]

It would be beneficial to add the 'use strict' directive to all cjs files in this repo. Strict mode can improve performance by eliminating some JavaScript features that hinder optimizations. It also helps avoid subtle bugs by enforcing more consistent scoping and variable declarations.

The MDN article on strict mode alludes to it, but the V8 JS engine used by Node will use more optimised execution paths when strict mode is enabled. See related Stack Overflow discussion for an example.

I'm happy to make a PR for this.

[escapedcat]

We only have like ~2 cjs in this project? Not sure what the impact would be. But sure go ahead.

[janbiasi]

Didn't know about that one, but I'd be very interested in seeing a benchmark of the effective difference! 👍🏽