while it's possible to use let keyword in for loop parentheses, it's not
possible to use it in if parentheses.

There are two use cases for this:

*1- if (let a = b()) a.c();*
 this can be done using optional chaining which is proposed:
b()?.c();

*2- if (let a = b()) c(a);*
this or more sophisticated patterns can't be done in any way other than
this:
let a = b();
if (a) c(a);

the problem here beside more line of codes, is *a *is defined outside of if
scope.
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while it's possible to use let keyword in for loop parentheses, it's not
possible to use it in if parentheses.

There are two use cases for this:

*1- if (let a = b()) a.c();*

this can be done using optional chaining which is proposed:

b()?.c();

*2- if (let a = b()) c(a);*

this or more sophisticated patterns can't be done in any way other than:

let a = b();
if (a) c(a);

beside more line of codes the problem here is *a* is defined outside of if scope.

while it's possible to use let keyword in for loop parentheses, it's not
possible to use it in if parentheses.

There are two use cases for this:

*1- if (let a = b()) a.c();*

this can be done using optional chaining which is proposed:
b()?.c();

*2- if (let a = b()) c(a);*
this or more sophisticated patterns can't be done in any way other than:
let a = b();
if (a) c(a);

the problem here beside more line of codes, is *a *is defined outside of if
scope.

while it's possible to use let keyword in for loop parentheses, it's not
possible to use it in if parentheses.

There are two use cases for this:

*1- if (let a = b()) a.c();*
this can be done using optional chaining which is proposed:
b()?.c();

*2- if (let a = b()) c(a);*
this or more sophisticated patterns can't be done in any way other than:
let a = b();
if (a) c(a);

the problem here beside more line of codes, is *a *is defined outside of if
scope.