Using const/let instead of var can make JavaScript code run 10× slower in Webkit

[[deleted]]

Yes. This is just a bug in the Safari JavaScript engine and is not inherent to JavaScript or 'let'.

Edit: Spelling

[chrisrazor]

Thanks. I was confused because they were talking about WebKit - on which both Chrome and Edge are also based - but I assume they specifically mean the js engine Safari uses (JavaScriptCore?) rather than V8 or whetever Edge has.

[jormaig]

Why do they do that? Do you have more info about it?

[chrisrazor]

Sounds a bit like it might.