It's been astonishing to me how people switched from var to let, but seem confused as to when to use const. I use const wherever I can since it's more appropriate for non-changing variables, and it helps me more easily visualize how a variable is being used in a block. But in other people's code I see a lot of letting all over the place. Maybe it's because of those articles saying to use let instead of var, but glossing over const.
Use const by default. If I need let, see if I can refactor to using const.
I've found that actually I can go far without using let, improving my code along the way.
I see a pattern from colleagues. They initialise a variable using let and then branch to figure out what should go inside it. That can be replaced by a pure function.
For loops tend to be the next thing. In that case, they can be replaced by higher order functions/methods without detriment to clarity (usually an improvement).
Perhaps the move towards iterators, with async support, will make it more common and legitimate. I haven't yet used those in a codebase but perhaps let in that instance leads to clearer code.
> They initialise a variable using let and then branch to figure out
> what should go inside it. That can be replaced by a pure function.
I don't want to detail the discussion, but I would love to see some of your code. I contend with this antipattern often but solve it in different ways often depending on language features. If you're doing anything other than simply calling an auxiliary method with a ton of parameters, I would appreciate seeing your solution in Javascript, a language that I'm learning but not proficient in.
maybe it’s because const is 2 more letters to type.
if “let” was “letitbe” I bet const would be more popular
seriously though, I wish they could have chosen a 3-letter word for const in keeping with var and let. I know const exists in other languages, but it doesn’t even mean the exact same thing as some other languages anyway.
It would have been nice to have `let` work like `const` does, and something else for what is currently `let` (`mut`?).
The TC39 was constrained by the list of reserved words though. `let` and `const` were reserved in ES5, and there was nothing that could have conveyed `mut`.
