Cons/Dislikes

No conventions.
Not standardized.
No consistency in online resources.
- Lots of outdated online resources.
- The fact that AirBNB has 20 pages on how to write JavaScript is insane.
No first class Enums
No types. Can be handled by Flow or TypeScript
Callback hell (work around with Promises, async and await, but its not supported everywhere)
Inconsisent: Array.length vs Set.size
- Like wtf?
All the problems of a loosely typed language.
- Hard to scale as a language, due to no types.
- Hard to refactor.
Inconsistencies in coding style amongst the community
JS Modules are confusing
Requires high code coverage due to inconsistencies.
Changing babel flags can make your code run differently
- Requires high code coverage to ensure it does as expected.
You need tools like lodash for basic stuff (bucketing items in in an array, groupBy)
Requires a lot of tooling to maintain JavaScript
Was design for client side browsing, not server side
It has both null and undefined
No native sprintf
Browser support is inconsistent.
- I ran into a problem with fetch() not being supported. https://github.com/github/fetch#browser-support
Requires a lot of static analysis tools.
- jshint http://jshint.com/about/
- flow
See Node.js's creator Ryan Dahl's "10 Things I Regret About Node.js"

What does this return?

"some string".match(/some regex/)

It's an Array with properties of index and input.

Things which increase the JavaScript environments complexity:

Requiring the use of new features via Babel
Requiring WebPack to bundle for frontend
Module systems
Inconsistent environments
- Browser development, so many browser versions
- Node, webpack vs everything else

Array.flat only works in Node.js 11+

Object.values(object) returns an array of values

array.values() returns an iterator

new Set(['a', 'b']) == new Set(['b', 'a']); // false

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