In ES6 strict mode: do function declarations within a block hoist?

# John Lenz (12 years ago)

That is to say, is this valid:

if (x) {
  f();
  function f() { doSomething() }
}

The same question applies to class declarations. I assume that top level class declarations hoist. (Where is this in the spec?)

That is to say, is this valid:

if (x) {
  f();
  function f() { doSomething() }
}

The same question applies to class declarations.  I assume that top level
class declarations hoist. (Where is this in the spec?)
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# Andreas Rossberg (12 years ago)

Yes, that is valid. Function bindings are initialised when entering a scope, all other declarations when their respective statement is executed -- before that any access will cause a ReferenceError (the so-called temporal dead zone).

In particular, classes don't "hoist", because their extends clause has to be evaluated at the right point in time.

On 5 June 2014 17:44, John Lenz <concavelenz at gmail.com> wrote:
> That is to say, is this valid:
>
> if (x) {
>   f();
>   function f() { doSomething() }
> }
>
> The same question applies to class declarations.  I assume that top level
> class declarations hoist. (Where is this in the spec?)

Yes, that is valid. Function bindings are initialised when entering a
scope, all other declarations when their respective statement is
executed -- before that any access will cause a ReferenceError (the
so-called temporal dead zone).

In particular, classes don't "hoist", because their extends clause has
to be evaluated at the right point in time.

/Andreas

# John Lenz (12 years ago)

Thanks.

Thanks.


On Thu, Jun 5, 2014 at 8:54 AM, Andreas Rossberg <rossberg at google.com>
wrote:

> On 5 June 2014 17:44, John Lenz <concavelenz at gmail.com> wrote:
> > That is to say, is this valid:
> >
> > if (x) {
> >   f();
> >   function f() { doSomething() }
> > }
> >
> > The same question applies to class declarations.  I assume that top level
> > class declarations hoist. (Where is this in the spec?)
>
> Yes, that is valid. Function bindings are initialised when entering a
> scope, all other declarations when their respective statement is
> executed -- before that any access will cause a ReferenceError (the
> so-called temporal dead zone).
>
> In particular, classes don't "hoist", because their extends clause has
> to be evaluated at the right point in time.
>
> /Andreas
>
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