71–80 of 223 posts
It's easy to forget to go "var me = this;" and use me instead of this inside of closures. But how would JSLint or JSHint know you made a mistake and didn't actually mean for "this" to be bound dynamically?
Why has it become popular for dynamic languages to conflate establishing a binding with assigning it a new value? Ruby, Python, and Javascript are all guilty of this. Scheme got it right sometime in the 1970's. (let ((x initial-value)) ; binding (set! x new-value)) ; assignment Or in infix syntax (Dylan): let x = initial-value ; x := new-value ;
Python doesn't let you write outside of local scope without a special keyword. Exactly the inverse of JS. If you want to write to global state, and you're aware that you're writing to global state, then you use the "global" keyword. That's all.
Do JSLint or JSHint catch the common error of using "this" inside a closure when you want it to be lexically bound instead of dynamically? It's easy to forget to go "var me = this;" and use me instead of this inside of closures. But how would JSLint or JSHint know you made a mistake and didn't actually mean for "this" to be bound dynamically?
It would be able to find out if you used an uninitialized me, _this, that though and complain. Using self as the this alias is really dangerous as it leaks to window.self so avoid it like the plague.
This is why I like both Scala and Coffeescript approaches. On Coffeescript vars are created for you, and on Scala, you can't not use it (you either use var or val, making it easy to change from re-assignable variables to final ones). Note that nowadays going to Coffeescript from Javascript is quite easy: http://js2coffee.org/
I don't know Coffeescript - does it implicitly create a local var when there is already a global with the same name?
In this case as long as OP was not using the variable in an enclosing scope, it would have been made local to the function.
Earlier quoted context omitted.
Hmm, so you wrote a careless typo while describing your "careless" coding? Not to be harsh, but maybe it's a hint?
Not to sound harsh, followed by something quite sarcastic and judgemental isn't a particularly nice way to address someone you don't know. I for one would speculate, not to sound harsh, that if you haven't made silly errors like this then you haven't been around the block enough times.
on the other hand, those of us who have been around the block enough times have almost certainly encountered co-workers who were bright, talented, cute, whatever - but at the end of the day were just ... sloppy ... lazy ... careless ... in their approach. It's a personality thing - they had nice childhoods, they never learned to by hyper-vigilant and paranoid, and as a consequence... they write buggy code that can't be trusted.
Reminds me of one of the more confusing bugs I've ever encountered in my life. I was throwing together a quick UI with Adobe Flex, and for some reason every time you clicked a particular button, the entire UI would shift 20 or so pixels to the right. I spent hours scratching my head until I noticed this for loop: for (x=0;x I wasn't declaring the x variable, so it was using the x part of the x/y positioning of the UI…
Reminds me of one of the more confusing bugs I've ever encountered in my life. I was throwing together a quick UI with Adobe Flex, and for some reason every time you clicked a particular button, the entire UI would shift 20 or so pixels to the right. I spent hours scratching my head until I noticed this for loop: for (x=0;x I wasn't declaring the x variable, so it was using the x part of the x/y positioning of the UI…
Now that I understand what you're saying: This is one of the reasons I hate the "feature" in C++ and C99 that you can declare variables anywhere. If you stick to declaring all your variables in one place, it's much easier to notice when you've already used a variable name.