Format + lint

[mlrawlings]

Switch to eslint and add prettier

Here's a link to the diff prior to running prettier:
https://github.com/marko-js/marko/compare/d7e529d401078817ee9cd4ab8887de9458956b4e

[coveralls]

Coverage decreased (-0.02%) to 90.363% when pulling dcae2cc on format-lint into ee17aa5 on master.

[coveralls]

Coverage decreased (-0.02%) to 90.363% when pulling 789cbd1 on format-lint into ee17aa5 on master.

[codecov]

Codecov Report

Merging #1016 into master will decrease coverage by 0.01%.
The diff coverage is 88.93%.

@@            Coverage Diff             @@
##           master    #1016      +/-   ##
==========================================
- Coverage   90.37%   90.36%   -0.02%     
==========================================
  Files         304      304              
  Lines       11536    11518      -18     
==========================================
- Hits        10426    10408      -18     
  Misses       1110     1110

Impacted Files	Coverage Δ
...ponents/taglib/TransformHelper/handleLegacyBind.js	88.33% <ø> (-0.73%)	⬇️
src/components/taglib/components-transformer.js	93.02% <ø> (ø)	⬆️
src/components/taglib/helpers/bindComponent.js	0% <ø> (ø)	⬆️
src/components/index.js	98.68% <ø> (ø)	⬆️
src/components/endComponent-browser.js	100% <ø> (ø)	⬆️
src/morphdom/specialElHandlers.js	84.84% <ø> (-0.87%)	⬇️
src/components/ready.js	53.84% <ø> (ø)	⬆️
src/compiler/util/parseJavaScript.js	81.87% <ø> (ø)	⬆️
src/components/beginComponent.js	100% <ø> (ø)	⬆️
src/components/taglib/preserve-tag-browser.js	100% <ø> (ø)	⬆️
... and 392 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ee17aa5...789cbd1. Read the comment docs.

[maxmilton]

Congrats on this! Nice to see some modern tooling going into the project 👍 🌟

I just wish you had used a 2 space tab width and single quotes... 😓

[mlrawlings]

@maxmilton We made the decision to just use the prettier defaults, however, it seems our .editorconfig has a tab width set and prettier is picking that up.

@marko-js/core Do we want to remove the .editorconfig and reformat or leave as is? I
don't have a preference myself.

As far as the single quotes, it looks like prettier may default to that in 2.0. We could go ahead and make the change now to avoid thrashing commits later... or we could wait. Thoughts?

[maxmilton]

Ah, I was wondering where the config came from! I didn't realise prettier will pick up .editorconfig files when there's no explicitly set value.

The other option that looks like it will change is trailingComma defaulting to es5 which would also make a big impact on this codebase. I say make the changes now but I'll leave that up to the core team 💙