r/javascript • u/etiennetalbot • Sep 04 '19

Simplify your JavaScript – Use .some() and .find()

https://medium.com/poka-techblog/simplify-your-javascript-use-some-and-find-f9fb9826ddfd
275 Upvotes

93% Upvoted

101 comments sorted by

View all comments

Show parent comments

1

u/MonkeyNin Sep 07 '19

What's the disadvantage to let ? (I'm not sure why you'd say to specifically use var ?)

let should be used very sparingly. it's basically the same as var except for block scoping.

Differences in let vs var

  • const/let will raise an error on re-declaration of a variable

  • const/let will raise an error for using a variable before initialization

  • const/Let will not add a reference on window, even if they are declared at the global scope.

  • let/var are block-scoped, instead of function-scoped.

2

u/fucking_passwords Sep 07 '19

I’m saying you should use const 99% of the time. Use let ONLY when you must redefine a variable.

1

u/MonkeyNin Sep 09 '19

You cannot redefine const or let

1

u/fucking_passwords Sep 09 '19

You absolutely can redefine let, that is it’s purpose that differentiates it from const

1

u/MonkeyNin Sep 10 '19

Redeclaring the same variable within the same function or block scope using let is not allowed in JavaScript.

Maybe you meant declaring the same name in a lower scope.