forbes at lindesay.co.uk (2016-09-16T09:55:26.633Z)
> If yes ... why would anyone write that ?
I think it would have to be "yes" (and that's probably just a contrived
example that doesn't demonstrate the usefulness).
Slightly less contrived, I could see the value in this, though. E.g.,
```js
router.get('/user', (req, res, next) => {
if (let user = req.session.user) {
// do stuff with user here
} else {
res.status(401).end();
}
});
```
I don't think it works as cleanly with `var`, but `const` and `let` has
some nice precedence with for-statements.
> If yes ... why would anyone write that ? I think it would have to be "yes" (and that's probably just a contrived example that doesn't demonstrate the usefulness). Slightly less contrived, I could see the value in this, though. E.g., ``` router.get('/user', (req, res, next) => { if (let user = req.session.user) { // do stuff with user here } else { res.status(401).end(); } }); ``` I don't think it works as cleanly with `var`, but `const` and `let` has some nice precedence with for-statements. On Thu, Sep 15, 2016 at 2:45 PM, Andrea Giammarchi < andrea.giammarchi at gmail.com> wrote: > > if( let a = ( let b = 10 ) * 3 > 10 ) > > I've honestly no idea, at first/quick read, what the hell that would > produce. > > Is `a` going to be just `true` ? 'cause if not, this proposal violates > operator precedence. > > If yes ... why would anyone write that ? > > On Thu, Sep 15, 2016 at 7:30 PM, J Decker <d3ck0r at gmail.com> wrote: > >> Why not more generally - allow let/var declarations in expressions? >> >> coming from a long and rich C background, I have no issues with the >> existing mechanisms... but for those languages that do support variable >> declarations in for loops; I've always wondered why not any expression? >> >> if( let a = ( let b = 10 ) * 3 > 10 ) >> ... or ... >> >> c = (let a = b*d) >> >> granted, the scope is extremely limited in the last case... >> >> _______________________________________________ >> es-discuss mailing list >> es-discuss at mozilla.org >> https://mail.mozilla.org/listinfo/es-discuss >> >> > > _______________________________________________ > es-discuss mailing list > es-discuss at mozilla.org > https://mail.mozilla.org/listinfo/es-discuss > > -- Jeremy Martin 661.312.3853 http://devsmash.com @jmar777 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.mozilla.org/pipermail/es-discuss/attachments/20160915/055a0c69/attachment.html>