4 ms·

I have used Javascript exclusively on client and server since late 2008. First Rhino and then Node. Before that I used Rails. I can understand the syntax gripe

I have used Javascript exclusively on client and server since late 2008. First Rhino and then Node. Before that I used Rails. I can understand the syntax gripes that some people have towards Javascript but I think this has more to do with a Ruby notion of "elegance" coupled with a lack of familiarity with Javascript then it does with actual issues with Javascript. In fact, I prefer Javascript to Ruby. I have gone the whole way with Prototype and then the whole way back. These days I prefer using just 20 or so functional DOM helpers rather than Prototype's Element extensions or JQuery's wrappers. A handful of DOM functions are significantly faster. As a result I have found it useful to keep third party dependencies to a minimum. A minimum of zero is working well for me so far. Writing raw Javascript is refreshing, even if it means a "prototype" here or there. I have written many "var" statements and have yet to see an undeclared variable pollute the global scope. I write for loops often. Sometimes I use forEach or reverse while loops. I don't seen any need for Coffeescript enumerators. I keep checking up on Coffeescript from time to time but I prefer the explicit syntax of Javascript. After spending hours refactoring code the Rails way, I have come to prefer code that's big-O efficient, as fast as possible, as direct as possible, and if it takes a few lines less that's great.

jashkenas 15y ago
You may have been misinformed -- the values of direct, raw, fast code are a big part of the reason why CoffeeScript works the way it does, and why many scripts can end up running faster after getting ported to CoffeeScript. The golden rule of CoffeeScript is to avoid adding any library code to the runtime, and to avoid introducing any special calls, to the greatest extent possible. Many folks rely on a "forEach" (or "each") iterator for all of their loops over arrays, because it's convenient. Unfortunately, it's also a very slow way to write an inner loop. CoffeeScript's comprehensions expand into regular JS loops over arrays and objects, so you get native speed, without the hassle. This: for item in list sum += item.amount Compiles into this JavaScript: var item, _i, _len; for (_i = 0, _len = list.length; _i < _len; _i++) { item = list[_i]; sum += item.amount; }
- augustl 15y ago
  I'd write that snippet the following way: for (var i = 0, ii = list.length; i < ii; i++) { sum += list[i].amount; } Or: for (var i = 0, ii = list.length; i < ii; i++) sum += list[i].amount; There are ways to make normal JavaScript not look ugly ;) EDIT: fixed minor oversight
  - haydenchambers 15y ago
    And where do you get item from?
  - jimbokun 15y ago
    The small bug in your code actually makes a good case for using the more concise syntax of coffeescript to help avoid those kinds of errors, while generating code that's just as efficient.
    - augustl 15y ago
      I disagree. In a real programming environment I'd notice immediately after running the code.
  - utkarshkukreti 15y ago
    Where are you setting `item` here?
  - TrevorBurnham 15y ago
    And I'd write for i in [0...list.length] by 1 sum += list[i].amount to get equivalent compiled output. I've used C and Java since high school, but I'm happy to be rid of that old `for` syntax. And I love that curly braces means only one thing in CoffeeScript: "I'm defining a new object with these key-value pairs."
- gavinlynch 15y ago
  Yah but your example for Javascript uses some dubious code. Did you know that "for .. in" loops are also native to Javascript? Why not use one for JS, why only Coffeescript? Also, it seems like you are doing some useless variable declrations. Let me rewrite it for you: 1) var list = [{amount:2}, {amount:5}], i, sum = 0; for (i = 0; i < list.length; i++) { sum += list[i].amount; } console.log(sum); 2) Or let's go even more simple... var list = [{amount:2}, {amount:5}], i, sum = 0; for (i in list) { sum += list[i].amount; } Personally, i don't find anything difficult about that.. Actually looks incredibly simple. What are you actually saving by using Coffeescript...? Some brackets, parens and a semi-colon? I don't know, those are just second nature for me. I've never really stopped and thought, "wow, if only I didn't have to type these extra parens, this is really killing me..." Not once.

jashkenas 15y ago

You may have been misinformed -- the values of direct, raw, fast code are a big part of the reason why CoffeeScript works the way it does, and why many scripts can end up running faster after getting ported to CoffeeScript. The golden rule of CoffeeScript is to avoid adding any library code to the runtime, and to avoid introducing any special calls, to the greatest extent possible. Many folks rely on a "forEach" (or "each") iterator for all of their loops over arrays, because it's convenient. Unfortunately, it's also a very slow way to write an inner loop. CoffeeScript's comprehensions expand into regular JS loops over arrays and objects, so you get native speed, without the hassle. This: for item in list sum += item.amount Compiles into this JavaScript: var item, _i, _len; for (_i = 0, _len = list.length; _i < _len; _i++) { item = list[_i]; sum += item.amount; }

augustl 15y ago
I'd write that snippet the following way: for (var i = 0, ii = list.length; i < ii; i++) { sum += list[i].amount; } Or: for (var i = 0, ii = list.length; i < ii; i++) sum += list[i].amount; There are ways to make normal JavaScript not look ugly ;) EDIT: fixed minor oversight
- haydenchambers 15y ago
  And where do you get item from?
- jimbokun 15y ago
  The small bug in your code actually makes a good case for using the more concise syntax of coffeescript to help avoid those kinds of errors, while generating code that's just as efficient.
  - augustl 15y ago
    I disagree. In a real programming environment I'd notice immediately after running the code.
- utkarshkukreti 15y ago
  Where are you setting `item` here?
- TrevorBurnham 15y ago
  And I'd write for i in [0...list.length] by 1 sum += list[i].amount to get equivalent compiled output. I've used C and Java since high school, but I'm happy to be rid of that old `for` syntax. And I love that curly braces means only one thing in CoffeeScript: "I'm defining a new object with these key-value pairs."
gavinlynch 15y ago
Yah but your example for Javascript uses some dubious code. Did you know that "for .. in" loops are also native to Javascript? Why not use one for JS, why only Coffeescript? Also, it seems like you are doing some useless variable declrations. Let me rewrite it for you: 1) var list = [{amount:2}, {amount:5}], i, sum = 0; for (i = 0; i < list.length; i++) { sum += list[i].amount; } console.log(sum); 2) Or let's go even more simple... var list = [{amount:2}, {amount:5}], i, sum = 0; for (i in list) { sum += list[i].amount; } Personally, i don't find anything difficult about that.. Actually looks incredibly simple. What are you actually saving by using Coffeescript...? Some brackets, parens and a semi-colon? I don't know, those are just second nature for me. I've never really stopped and thought, "wow, if only I didn't have to type these extra parens, this is really killing me..." Not once.