Hacker News Reader

Comment by jashkenas | Hacker News Reader

Just realized that Crockford didn't link to it in his post. Here's the full proposal that Brendan Eich added to the ES Wiki: http://wiki.ecmascript.org/doku.php?id=strawman:arrow_functi...

View on HN

Was: From my understanding of binding, this proposal means that the fat arrow can't be used to define 'methods' on a prototype.

Edit: as per parent article, use (this, x) => { this.property = x; } instead of ->

That is usually not my problem -- I need it to bind this when I am making a for or map loop or registering a callback handler.

The part I found interesting was:

"However, we don’t want CoffeeScript’s ->, it’s confusing to have two arrows and dynamic this binding is an oft-fired footgun."

It looks like Eich's original pitch was for both => (lexical this) and -> (dynamic this), but the latter was cut for political reasons.

Out-of-band info from here:

https://twitter.com/brendaneich/status/186156717506166784

https://twitter.com/brendaneich/status/186160406300082176

https://twitter.com/brendaneich/status/186162306521120770

https://twitter.com/brendaneich/status/186162532367601666

Thanks. Interesting!

I'd be interested to hear from any regular user of CoffeeScript who finds -> vs. => confusing.

I didn't know what to make of that comment. Dynamic this-binding is used heavily in any OO javascript code; it's not a feature that should be ignored when designing the new syntax.

To me, writing 'this' as part of the parameter list for methods is more confusing than having a second arrow operator.

Reply on news.ycombinator.com