feat: use let instead of var

[Le0Developer]

Is your feature request related to a problem? Please describe. js-confuser generated code uses var instead of the preferred let alternative.

js-confuser using var makes reverse engineering easier, because it eases differentiating between js-confuser generated and normal code.

Before upgrading to the latest version, I was simply replacing all var with let and then shoving it into esbuild, which … worked! Now, it fails due to (I'd assume) control flow changes (erroring due to redeclaration of var).

Describe the solution you'd like Always use let instead of var.

If support for older JS runtimes is required, the user could always shove the output into another transpiler.

[MichaelXF]

Hi you're right. JS-confuser only places var right now. The obfuscator has a much easier time dealing with var code and dislikes the use of let and const

For instance, Control Flow Flattening completely ignores blocks of code that use let/const due to the lexical bindings having stricter rules.

Being able to differentiate between obfuscator code (var) and user code (let) is a big flaw, so here are solutions:

1) Make the obfuscator use let so there is no difference (all let solution) 2) Change the users code to use var, and keep obfuscator using var (all var solution)

What do you think?

[Le0Developer]

I'd prefer all let, because doing var -> let yourself is a lot harder than let -> var (if you need the other for some reason).