snake_case, camelCase, and other Misadventures in Coding Standards

some_programmers_like_snake_case while othersPreferCamelCase (and dont-talk-to-me-about-css-or-html) but life really becomes entertaining when different programmers — sorry “software engineers” — enforce their preferences locally.

Consider a service, implemented in python (where snake_case_is_popular) that passes data to a web application, i.e. javascript (whereCamelCaseIsPopular). You might end up with a data structure like:

    my_id: 17,
    my_name: 'seventeen'

In modern Javascript, you could write something like:

const { my_id, my_name } = await getSomeData()

And get on with your life.

But it won’t lint, because someone has enforced camelCase in your project lint rules, so now you write:

const data = await getSomeData()
const myId = data.my_id
const myName = data.my_name

And now your code lints.

No problems!

One day, you discover a problem with the data in myName and it stymies you for a bit until you find the assignment statement that renamed the value and you’re reminded that it gets populated from a service with the property my_name and you figure it out.

No problems, right? Chalk it up to experience.

After a lot of this, you kind of wish the problem would just disappear, so you do something like write snakeToCamel which converts an object with snake_case properties into an object with camelCase properties, and now you can write:

const { myId, myName } = snakeToCamel(await getSomeData());

And your code is nearly as clean as if you, say, had turned off the camelCase lint rule in the first place. But hey, snake_case is nauseating.

Later, you modify the helper library that builds async data methods (after all, snakeToCamel called on a conforming object is a no-op, isn’t it?!) so that snakeToCamel always gets called, and now you can finally write:

const { myId, myName } = await getSomeData();

You can now write a new lint rule that flags redundant inline calls to snakeToCamel so that every time a file gets touched, the redundant calls are flagged, or flex your awesomeness and write a code-transform to remove them all in one glorious diff.

Now, your code is beautiful, it’s all in camelCase, and it’s sleek and elegant and oh-so-2017…

Except that there’s no clue in the code for someone hunting down a reference to myName that it might be called my_name deeper in the pipe (e.g. in the Network tab), and now you have a bunch of folks bikeshedding about how things like my_uuid or inner_html should be treated. Because innerHTML does not work well in the other direction, and the python folks have their own lint rules…

Also, deep in your service layer, some dodgy regex is rewriting every property name you ever see, and it’s probably completely clueless about unicode (quick quiz — which unicode characters are OK in javascript variable names?! I looked up the answer and you don’t really want to know.) So, that’s definitely never coming back to bite you.

But hey, at least you don’t have to look at a mixture of snake_case and camelCase in your source code, because the cost of that is… zero?