Chunkwm combined with Karabiner-elements has completely changed how I interact with a computer. It feels more like an extension of me, similar to the feeling of rapidly iterating through commands in a CLI.
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I have been using it for about 2 years now.
I think my main concern going forward would be a diaspora of open source projects.
One of the neat things about Github is that a ton of open-source projects can be found there. Regardless of how Github operates going forward for individual users, I would be surprised if projects like Facebook's React or Google's Angular remained on a platform controlled by Microsoft.
Those are only two examples in a sea of OSS projects, so maybe the impact will be smaller than I think.
I think that Tom Dale made a pretty good argument of why to avoid CoffeeScript as part of his argument for TypeScript.
"For example, CoffeeScript adopted for..of loops to iterate over the properties of an object. Meanwhile, ES6 introduced its own for..of loops as a way to loop through iterable objects. If CoffeeScript wants to support new functionality with similar syntax like this, it has two choices: break existing CoffeeScript code, or diverge from JavaScript more and more over time."