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.
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.
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.
"set" or "fix" would be quite nice, given what const actually does.
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`.
https://mathiasbynens.be/notes/reserved-keywords#ecmascript-...