2 ms·

That use of `with` makes me squeamish as hell. Also, on the topic of the "eta" function, it's odd that the author seems unaware of existing implementations of

That use of `with` makes me squeamish as hell. Also, on the topic of the "eta" function, it's odd that the author seems unaware of existing implementations of `bind`.

invisiblefunnel 15y ago
Crockford warns against ever using `with` in a talk he gave last year. Discussion on `with` at 19m58s: http://ontwik.com/javascript/douglas-crockford-javascript-programming-style-and-your-brain/ http://ontwik.com/javascript/douglas-crockford-javascript-pr... Edit: He says it's not that `with` isn't useful, but that there is never a case where it isn't confusing.
- mistercow 15y ago
  That is very well put. It is a shame that JS got its scoping so very upside-down, because it means that tiny changes in code can cause incredibly confusing and initially undetectable bugs. `with` is basically an infected bandaid on a broken system. It seems like it's helping until you notice the smell.
- insin 15y ago
  Sure there are - why are so many Crockford pronouncements taken as a signal to stop thinking? Notice that his "with is bad" examples (which are usually bad examples and bad usages [1]) always involve contrived examples of potentially ambiguous assignment - one of the more useful ways to use `with` is with objects whose properties are DSL-like functions, named in such a way that there's no mistaking their origin and with no ambiguous assignment involved. Simple example with includes: https://github.com/insin/DOMBuilder/blob/master/examples/reddit_posts.html#L18-47 https://github.com/insin/DOMBuilder/blob/master/examples/red... More extensive example of inheritable templates for a CRUD admin app: https://github.com/insin/sacrum/blob/master/lib/sacrum/admin.js#L277-439 https://github.com/insin/sacrum/blob/master/lib/sacrum/admin... [1] http://webreflection.blogspot.com/2009/12/with-worlds-most-misunderstood.html http://webreflection.blogspot.com/2009/12/with-worlds-most-m...

That use of `with` makes me squeamish as hell. Also, on the topic of the "eta" function, it's odd that the author seems unaware of existing implementations of `bind`.

invisiblefunnel 15y ago

Crockford warns against ever using `with` in a talk he gave last year. Discussion on `with` at 19m58s: http://ontwik.com/javascript/douglas-crockford-javascript-programming-style-and-your-brain/ http://ontwik.com/javascript/douglas-crockford-javascript-pr... Edit: He says it's not that `with` isn't useful, but that there is never a case where it isn't confusing.

mistercow 15y ago
That is very well put. It is a shame that JS got its scoping so very upside-down, because it means that tiny changes in code can cause incredibly confusing and initially undetectable bugs. `with` is basically an infected bandaid on a broken system. It seems like it's helping until you notice the smell.
insin 15y ago
Sure there are - why are so many Crockford pronouncements taken as a signal to stop thinking? Notice that his "with is bad" examples (which are usually bad examples and bad usages [1]) always involve contrived examples of potentially ambiguous assignment - one of the more useful ways to use `with` is with objects whose properties are DSL-like functions, named in such a way that there's no mistaking their origin and with no ambiguous assignment involved. Simple example with includes: https://github.com/insin/DOMBuilder/blob/master/examples/reddit_posts.html#L18-47 https://github.com/insin/DOMBuilder/blob/master/examples/red... More extensive example of inheritable templates for a CRUD admin app: https://github.com/insin/sacrum/blob/master/lib/sacrum/admin.js#L277-439 https://github.com/insin/sacrum/blob/master/lib/sacrum/admin... [1] http://webreflection.blogspot.com/2009/12/with-worlds-most-misunderstood.html http://webreflection.blogspot.com/2009/12/with-worlds-most-m...