refactor(typescript): refactored code to use typescript

[dvelasquez]

This PR refactors the code to use TypeScript instead of VanillaJS.

Changes

• Updated eslint to handle typescript code
• Refactored source files to typescript
• Refactored test files to typescript
• Fixed some issues with the tests
• Updated package.json to expose CJS and ES Modules
• Created Type Definition for the PageXRay module

[mrchrisadams]

HI @dvelasquez, I've had a chance to look over this, and I really like it - thanks for taking the time to work on it.

I'd like to merge this in with fresh eyes though, so I'm going to check tomorrow to see what changes might be needed in code that consumes the earlier released version of co2.js, then then, and update the changelog and README, to prep for a new release.

Much gracias 👍

[dvelasquez]

Hey! It would be really interesting to try this branch with a project that uses this as a dependency, to check if everything is ok

[mrchrisadams]

Indeed!

Sitespeed would be the big one, as it's in production in a few high profile places. Here's an example of their public dashboards:

And below is the direct link to the chart:

https://dashboard.sitespeed.io/d/000000060/leaderboard?orgId=1&from=1603728284785&to=1604333084785&var-namespace=sitespeed_io&var-path=alexaDesktop&var-domains=All&var-pages=All&var-browser=chrome&var-connectivity=cable&var-function=median&viewPanel=79

I had planned to:

• a checkout of sitespeed
• update the dependencies to point to this branch
• run the tests and see if we get the numbers

This here where it's in use in the sitespeed codebase:

https://github.com/sitespeedio/sitespeed.io/blob/main/lib/plugins/sustainable/index.js#L8-L13

And the tests looked like this, but they've since been moved into a separate repo:

https://github.com/sitespeedio/sitespeed.io/pull/2868/files

[drydenwilliams]

Looks pretty great to me 👍

note: haven't run it locally

[mrchrisadams]

hi @dvelasquez thanks so much for this PR. I'm going to close this, as there have been a bunch of changes since this PR was initially created - both in this project, in typescript and in javascript too.

Porting this to typescript isn't on the short term roadmap for now, but we're collecting any discussion in the issue below, about whether to add it later:

#77

[dvelasquez]

No problem, let me know if you want me to tackle this again in the future.