My theory of tab width is that it should be somewhat proportional to the average height of indented sections of code in that language.

That is, if a given language is really verbose and requires a lot of code to do simple things, the functions, if-statements, loops, etc will probably be a lot longer (like in C or Go) and so you need wider tabs to help visually align things.

But if a language encourages a style where functions are just a couple of lines long, if statements and loops are rare (or at least comparatively short), having excessively wide indentation can hinder readability.

Lots of developers work at Google, which enforces the use of two space tabs internally.

Personally I’ve come to appreciate it (and even prefer it).

Someone (@feross) created something called StandardJS, and even bought the domain standardjs.com, and started advertising it as a great style guide. I initially thought it was a joke or parody, as my own style is pretty much opposite of the guide.

Anyway, it says to use two spaces. It got super popular and here we are now.

It's pretty accepted style. E.g. https://google.github.io/styleguide/jsguide.html#formatting-...

Ruby infected webdev with this awfulness.