Best Practices Exist For A Reason

http://tomdale.net/2012/04/best-practices-exist-for-a-reason/

by jashkenas • 14 years ago

248 97 14 years ago

jashkenas2• 14 years ago

The main problem with appealing to "best practices" is this: One man's best practice is another man's anti-pattern.

Between semicolon-free folks and JavaScript traditionalists, who gets to play the role of the expert? If Node.js is popular, does that mean that Isaac's comma-first style is "correct"? (https://gist.github.com/357981)

In the absence of a quantitative engineering method with which to evaluate either approach, isn't it a purely personal and political choice?

j_baker• 14 years ago

You can't solve everything with numbers, and I say this as someone who believes very strongly in data-driven decision-making. Even given perfect data as far as what practices are more effective, you still have the problem of interpreting it. This adds its own layer of purely personal and political choices.

My advice? Don't work with people whose best practices are your anti-patterns. Or at least strive to work with people who agree with you on a core set of principles. Or hell, work with people who agree with you on nothing. Just don't complain when you can't work with any of them. :-)

And besides that, what's wrong with "purely personal and political choice[s]"? Being that I'm the person who's writing my code, I'm allowed to make a certain number of purely personal choices. That is, as long as I take into account the political consequences of doing so. Put another way, it's ok to have personal preferences, but you have to take other peoples' feelings into account too.

InclinedPlane• 14 years ago

The problem here is viewing software development as some sort of monolithic phenomenon. "Software development" is a crude moniker that covers an incredibly wide variety of efforts, varying in scale, detail, and significance across a much wider range than anything else we consider to be a single discipline. "Best practices" for development of an iphone game may not be the same as for flight software for an orbital rocket or for an international banking backbone.

Edit: to use an analogy, imagine if all vehicle development was treated with the same terminology. Whether you're building helicopters, spacecraft, mass produced commuter cars, RC toys, nuclear powered submarines, formula 1 race cars, or tunnel boring machines: all of it is just vehicle manufacturing right? Just as anyone would find it ridiculous to put forward advice that could possibly apply across all of those distinctly different disciplines we should view advice about software with the same skepticism.

cube13• 14 years ago

The problem is that the industry, as a whole, is still extremely young, and simply hasn't had the time to develop a standard set of good, let alone best, practices. Tools and processes are changing at a rapid rate, and it will simply take time for best practices to sort themselves out.

>"Best practices" for development of an iphone game may not be the same as for flight software for an orbital rocket or for an international banking backbone.

I disagree. There are a few things that should be common across all of these, like not storing passwords in plain text.

amackera2• 14 years ago

That example gist went a long way towards convincing me of isaacs' comma prefix style.

To me, consistency is important. All of my codebase is traditional comma postfix, so I'll keep using that; however, maybe with some new projects I'll try on the comma prefix pants and see if it helps.

Thanks for the link!

jashkenas2• 14 years ago

To play at devil's advocate, please don't. Otherwise you should have written your comment like this:

    To me
    , consistency is important
    . All of my codebase is traditional comma postfix
    , so I'll keep using that
    ; however
    , maybe with some new projects I'll try on the comma prefix [...]

... using typography in a typographically sensible way is far more important to readability than an arbitrary "consistency" of punctation. We're humans, not computers, after all.

ynniv5• 14 years ago

That example gist went a long way towards convincing me of isaacs' comma prefix style.

What convinced you? I read it and saw something wildly different, which is best reserved for a good reason. The reason appears to be visual recognition of delimiter mistakes that the parser will catch anyway.

The gist contains examples of various mistakes in both styles. Most of the errors are syntax error which will be immediately rejected by a parser. While the comma first errors are generally more obvious, they are silently bad by unexpectedly returning undefined. The standard "var" example is silently bad by leaking vars into the global scope when chaining initializers on a single "var". My conclusion from these samples is that comma prefix formatting only practically helps to prevent hidden mistakes in chained "var"s. Putting each variable declaration on a line of its own is far less distracting than reformatting every list and object.

Sample comma first style error. This seems like a strange thing to do, but I'm unfamiliar with this style.

    return
      { a : "ape"
      , b : "bat"
      } // returns undefined,
        // then creates a block with two named statements.

Sample standard style error:

    var a = "ape eat banana",
      b = "bat, allowed to fly",
      c = "cat toy",
      d = "dog chasing the mailman,"
      e = "elf lord",
    ....
    // leaks "e" into global scope

bentlegen4• 14 years ago

I think using comma-first syntax as a counter example is disingenuous. Whether you're a novice programmer or an expert programmer, using comma-first or comma-last isn't going to bite you in a way that isn't immediately solvable.

Omitting semi-colons, however, can cause novice JavaScript programmers serious grief. Nevermind novice JavaScript programmers – they cause me grief, and I put semi-colons everywhere! That's because I'm often called in to debug our customers websites, and on several such occasions I've had to fix bugs that never would have occurred if that customer used semi-colons properly.

Sure, if our customers understood JavaScript's ASI and how to use semi-colons "properly", I wouldn't have this problem either. Except, as Tom points out, the reality is that almost none of these people will invest in doing so.

btilly5• 14 years ago

Whether you're a novice programmer or an expert programmer, using comma-first or comma-last isn't going to bite you in a way that isn't immediately solvable.

Really?

The comma first style makes it less likely that your list will end with a trailing comma, which can cause IE-specific bugs. If you're trying to track down the IE breakage a couple of weeks after you wrote down the code, it can be fun to track down the extra comma. If you don't know that this bug is possible (as I'm guessing you don't), multiply the hair-pulling by 10.

See the cautionary story in http://www.enterprisedojo.com/2010/12/19/beware-the-trailing... for a real life example.

With the comma first style, that bug would never have been introduced. Neat, huh?

mattbriggs3• 14 years ago

It's not about omitting semi-colons, it is about treating special cases as special cases. I just wrote something about the goals of NPM style, and how it can help debug those nasty problems http://mattbriggs.net/blog/2012/05/03/npm-style-javascript-i...

adamesque• 14 years ago

The root problem is that we still don't know how to disagree when two sides look at the same set of data and believe two different things. We allow ourselves to descend into tribalism and assume the worst of each other.

If you look at the language Tom objects to the most, it's language Isaac uses that promotes this tribal attitude that the other side doesn't have your best interests at heart, and questions their motives.

We're just terrible at this, and I'm not sure any human society has ever really cracked it.

chefsurfing• 14 years ago

Didn't the Greeks crack it with the Trivium? http://www.triviumeducation.com/

freshhawk9• 14 years ago

I completely disagree. We absolutely know how to resolve these kinds of disputes and it's very accurate (not as accurate as Science, but better than everything else). See my other comment here (http://news.ycombinator.com/item?id=3922527).

The tribal attitude is the enemy of this process for sure, and humans are very prone to that attitude but that doesn't mean you can't still find the answer more likely to be right.

mcguire• 14 years ago

Who gets to play the role of expert? Presumably the "leaders in this language community" who "have given [everyone] lies and fear", according to Isaac's referenced blog post.

In the absence of a true quantitative engineering method, there is a middle ground other than personal choice: common anecdotes. Presumably, those shameful leaders have heard enough stories about the issue to make a reasonable recommendation, sort of like advising against shipping server software with an open default security strategy even though I don't have any peer-reviewed studies saying such is unwise.

phillmv• 14 years ago

I find this amusing.

Stylistically, I side with the no semicolon people. Grammatically they're redundant.

Pragmatically, if you ever find yourself saying "read this enormous, hard to read spec just so you can identify the three or four edge cases that will burn (yet remain statistically likely to commit)" you are on the losing side of history.

Basically, it's preposterous to have reasonably smart people seriously argue that the option that is least user friendly and most likely to cause pain down the road is the best one out of a sense of misguided spec puritanism.

keyist• 14 years ago

"Between semicolon-free folks and JavaScript traditionalists, who gets to play the role of the expert?"

You're framing this as a disagreement between equals. It is not. There are degrees of expertise. (Total lines of production code * amount of usage) is a reasonable approximation, and those who rank highest on this scale are overwhelmingly in favor of requiring semicolons.

If Carmack and Torvalds were in agreement on a C best practice while Odesker^W^W^W^W^W^W^W Topcoder user #12571 said to do something else, I wouldn't go with the latter.

Google, responsible for a JS engine, multiple compilers that target JS, and what is likely to be the single largest JS codebase of any company: http://google-styleguide.googlecode.com/svn/trunk/javascript...

Brendan Eich: "The moral of this story: ASI is (formally speaking) a syntactic error correction procedure."

Or you can go with the Node.js guys.

Darmani5• 14 years ago

You can think about the effect of coding style instead of letting the experts think for you.

If you are doing a Topcoder round, then the random Topcoder user's advice is probably better than Carmack's. Carmack or Torvalds would probably tell you to use a variable name that gives a lot of information about its purpose, so that other people will find it easier to read your code. The Topcoder user might tell you to use a cryptic abbreviation that helps you remember a variable's purpose but clues little to the outside reader, since Topcoder users are penalized for allowing others to find their bugs. When implementing an algorithm, Carmack or Torvalds would code it as part of an extensible system with an API so that it can be used for many purposes. The Topcoder user might code it with no potential for reuse, but would do it in the way easiest to code quickly without making a mistake.

no_more_death• 14 years ago

Brendan Eich does not oppose ASI.

Error correction simply means "add a semicolon if it's necessary."

mattbriggs3• 14 years ago

Brandon Eich on twitter (or in comments here) will also say that it is his opinion, and he recognizes that it seems to work pretty well for the NPM guys, but maybe it is just because they are such great devs, he doesn't see it scaling down that well.

And google is well known for terrible quality javascript. http://www.sitepoint.com/google-closure-how-not-to-write-jav...

And finally, Crockfords reasoning about things like this seems based on the presumption that js developers are drooling idiots. For example, he recommends against using the new keyword for object creation in javascript, even though object factories can often be a huge waste of memory, because dumb javascript developers may forget to use the new keyword at times when they want to instantiate objects.

I am not saying you shouldn't listen to smart people, but I am saying that you should actually learn the reasons they say the things they do, and use your own brain when making choices.

freshhawk9• 14 years ago

"In the absence of a quantitative engineering method with which to evaluate either approach, isn't it a purely personal and political choice?"

No.

Here's one idea: perhaps everyone's opinion is not equal on every subject. Perhaps by looking at the opinions of respected accomplished people who have garnered the respect of other respected accomplished people you can being to see who's opinion should get more weight. This is the process that came up with the very ideas of things like "engineering" and "quantitative".

I know we love the young upstarts disrupt the old way of thinking meme. That's why you framed it this in that way with the folks vs the traditionalists. You might want to remember that historically the young upstarts have been wrong 99% of the time. That's why it's news when they are right.

"One man's best practice is another man's anti-pattern"

And in the vast majority of cases, when you ask that question about a specific problem: One of those men is wrong. Even if they're both smart. But how to tell? If a huge number of other smart and experienced people have been convinced by one of them ... well I'd go with that guy. You won't be right all the time but it's the best system we've come up with so far for things that don't conform to double blind placebo controlled studies or mathematical proofs. It literally is the best way to be right most often.

Produce4• 14 years ago

>And in the vast majority of cases, when you ask that question about a specific problem: One of those men is wrong. Even if they're both smart. But how to tell? If a huge number of other smart and experienced people have been convinced by one of them ... well I'd go with that guy. You won't be right all the time but it's the best system we've come up with so far for things that don't conform to double blind placebo controlled studies or mathematical proofs. It literally is the best way to be right most often.

This reminds me a lot of abstraction in software systems. For 95% of cases, the abstractions make things quicker in the end. For those 5% of edge cases which the abstractions don't cover properly, you spend inordinate amounts of time trying to get things to fit. The bigger point here is that trying to white-wash anything with a particular methodology is both the right and wrong thing to do. It's right because most of the time it will work, it's wrong because when it doesn't work, you will have a hell of a time dealing with it.

The best system we have come up with so far is actually to take things on a case-by-case basis instead of trying to solve everything in one fell swoop. The problem is that one must be mindful as consistently as possible to achieve this. Most people are not capable of keeping that line of focus for an hour, let alone a day or their whole lives. Funnily enough, the solution to this is meditation, not a set of best practices or expert opinions.

papatron• 14 years ago

"If a huge number of other smart and experienced people have been convinced by one of them ... well I'd go with that guy"

This will answer the question, "who is best at arguing their point". It does not reliably answer, "whose point is correct?"

Isofarro3• 14 years ago

"Between semicolon-free folks and JavaScript traditionalists, who gets to play the role of the expert? If Node.js is popular, does that mean that Isaac's comma-first style is "correct"? (https://gist.github.com/357981)

No. Isaac doesn't define what style node.js is written in. And in an interview when he took on the lead developer role on he affirmed that he would abide by their current coding preference, which wasn't comma-first. That's Isaac in a nutshell, he works with the developers around him.

You may be mistaking Node.js with npm. npm is Isaac's code, and that is comma-first I believe. It's his project, and his rules, and his call as to what coding style he wants. People who participate in his projects either accept that, or walk away. Node.js is an existing project, so the existing coding preferences are in place -- unless, I guess, there's a general consensus that the coding preferences in place are causing an issue.

Produce4• 14 years ago

It's surprising that we haven't managed to create languages/editors which can break code down into atoms which can be presented however the developer working on said code likes. E.g. if a segment of code was tokenized properly and the editor could manipulate those tokens, coding style issues would become a thing of the past.

benatkin• 14 years ago

First, Isaac Schlueter isn't advocating against best practices with ASI. He's advocating for an alternate best practice that you disagree with. In that very article he suggests an alternate place to put the necessary semicolons.

Second, the CouchDB thing isn't because of a lack of best practices, it's because the wrong best practices were misapplied. And in the end, its use of best practices prevented it from severely hurting CouchDB's reputation.

The best practice is that password data should be stored as a salted hash, so if the database is compromised, the original password can't be retrieved. It's rare that the salted hash is intended to be public information, and that's what the CouchDB people did. What they should have done is realized that since they're deliberately sharing the hashed passwords, the original best practice doesn't apply, and they need to break it down and reexamine it (probably a good idea anyway for a project of its size). And they should have reached the conclusion that SHA1 is much too weak and/or that the salted passwords shouldn't be shared. In the new version, CouchDB 1.2, where an effort to correct the problem was made, the passwords aren't public. But at least, aside from the encryption strength, they got the hashing right, in that they used salts so rainbow tables can't be used. SHA-1 is easy to brute force for simple passwords, but as passwords get longer and contain more than dictionary words, it gets harder to brute force. It's easy to communicate that they screwed up, and easy to communicate that it's no worse than Sony password databases that were compromised, but the truth lies somewhere between the two, and can be seen by carefully considering the details of the case.

Daniel_Newby• 14 years ago

> The best practice is that password data should be stored as a salted hash, so if the database is compromised, the original password can't be retrieved.

The best practice is to use a purpose-built password algorithm like bcrypt. Algorithms like SHA1 and MD5 are designed to run fast; even with salts they can be cracked by massively parallel hardware like a room full of GPUz.

ehutch79• 14 years ago

you can't have alternative best practices... the BEST in best practices kind of makes that clear.

best practices and most practical practices are not always the same though.

fizx• 14 years ago

With respect to style and syntax at least, this is why I like golang. There is one true way to format a go program, and there is a compiler/autoformatter to enforce it.

bitops• 14 years ago

JavaScript and semicolon controversy aside - I'm always happy when I read a post written in this style. It's clear (at least to me) that the author has taken the time to think about what they're saying, and they present clear arguments. I always hope that more people write this way; in the style of what I feel is real discussion.

madhadron2• 14 years ago

The real question is why anyone takes obviously wrong artifacts in JavaScript like omitting semicolons and flagrantly wrongly designed this binding seriously. This isn't an issue of best practices or personal preferences, it's aspects of a ubiquitous language that are simply and unequivocally broken.

tikhonj• 14 years ago

This just begs the question: they're broken, because they're broken? And anybody who thinks the features neat is wrong?

The reason people talk about omitting semi-colons in JavaScript is because they don't think that feature is unusable--they clearly think it's better than adding semi-colons everywhere! When reasonable people disagree like that, the situation is rarely simple and clear-cut.

Now, perhaps you could reasonably argue that the behavior is unfortunate. But you can also reasonably argue the converse. And, most importantly, it isn't immediately clear who is correct.

JamisonM• 14 years ago

It has always been a mystery to me that reasonable people somehow think it is better to omit the semicolons where you can instead of just being 100% consistent by using them to terminate every statement. I have always thought that computers, programming, logic were always all about favouring consistency and simplicity. My mind boggles that otherwise talented people do not see the value in using simpler rules when they work and avoiding exploiting complex things that seem to offer somewhere between little and no extra value.

I guess I just don't get it because it has always seemed precisely a simple and clear-cut thing to me but somehow it is not.

madhadron2• 14 years ago

Yes, they're wrong, because they make certain classes of errors impossible to catch automatically, and place that much heavier a burden on me to use the tool. You can do what you like in private, but forcing me to waste my mental energy because it makes you feel good about yourself to be able to manage lots of complicated trivia? Should I be accepting if you wanted me to use a hammer with a spike on the side of the handle?

mistercow• 14 years ago

>By couching it in these terms, it implies that anyone who follows best practices has given in to “lies and fear!” Who wants to be swayed by that?

That is some fairly brazen rhetorical sleight of hand. Schlueter is obviously not attacking the following of best practices. He is saying that semicolons-everywhere isn't a best practice and he gives an argument that the most common rationales given for the practice do not hold water. There are a few flaws with his argument, but what it certainly is not is a general condemnation of the following of actual, bonafide best practices.

Pretending otherwise is akin to accusing someone of "siding with the terrorists" because they argue that people should be allowed to take bottled water on airplanes.

jtchang• 14 years ago

This is my love/hate relationship with JavaScript. There is often more than one "correct" way to do things and there is a lot of disagreement in the JS community about what way is "best".

Contrast this with Python where the overarching rule is there should be one, and preferably only one, obvious way to do things.

artsrc• 14 years ago

These kind of support your position:

http://www.python.org/dev/peps/pep-0008/#tabs-or-spaces

The most popular way of indenting Python is with spaces only. The second-most popular way is with tabs only. For new projects, spaces-only are strongly recommended over tabs.

Function names:

...

mixedCase is allowed only in contexts where that's already the prevailing style (e.g. threading.py), to retain backwards compatibility.

bertzzie• 14 years ago

Also relevant: Most best practices exist without explanation. We are supposed to just use it without question. I think that's what Issac meant with "fears and lies" (not that I agree with his statement). Raymond Chen puts it great:

Good advice comes with a rationale so you can tell when it becomes bad advice. If you don't understanding why something should be done, then you've fallen into the trap of cargo cult programming, and you'll keep doing it even when it's no longer necessary or even becomes deleterious.

source: http://blogs.msdn.com/b/oldnewthing/archive/2009/11/04/99170...

madrobby• 14 years ago

Good to know that depending on the author of an article, some stories don't get flagged and disappear from the front page of hacker news.

jimmyjazz14• 14 years ago

Many best practices work well because they mean you don't ever have to think about uninteresting problems (like ASI) ever again. I know the rules of ASI but I honestly have never had to think about them because, I don't need to; I just put a semicolon at the end of my lines.

If you ever have to do network and systems administrations you will come across loads of best practices because needing to memorize every last rule and edge case of all the software on your systems would be truly maddening.

That said, it is always good to know the why behind best practices and not follow them blindly.

nherment• 14 years ago

Very well written post.

However, I found it to be of little value. When fully reading Isaac's post (http://blog.izs.me/post/2353458699/an-open-letter-to-javascr...), it appears to not diverge much from what you've written.

I consider myself a beginner in Javascript and did not find Isaac's post the least condescending. I actually learned a few things and am very glad he took the time to explain how things work. Because honestly, I won't read the ECMAScript spec unless I need to.

I'm actually one of the people who never use semi-colons to terminate statements. That's for personal projects. Where I work, we (as a team) decided to use them. And that's fine, but I prefer not to use them.

evanlong• 14 years ago

And that is why... you use node.js. checkout out @whyyouusenodejs on twitter.

hef19898• 14 years ago

If I could I would up-vote this post twice at least! And it is not the Java, node.js, where-do-you-put-your-semicolon part of it. I don't undersand any of it. No, it is more the view on best practices. And there, I completely agree.

I'm part of HN not for very long, but what strikes me are the similarities between supply chain management and programming in some aspects. The purely technical issues are out of scope here since I cannot judge them, it's more about the principles behind. Like in this case here.

Best pratices provide a guideline and are condensed experience. They are by no means the only or best solutions, rather ones that can be applied in a lot of cases withou screwing up. That said, one should also reach a point where understand them. One has to in order to understand when to use them, most people get at least to that point.

What you actually have to do is reach an understanding of not only when to use best practices but one of knowing why you use them. This is not true mastery, but it will get you far enough.

Ultimately, you need people who know when to use a best pratice, when to ignore them and when to actually brek conventional wisdom. What I see a lot lately is people doing the last to bits without having understood the best pratice's when and why in the first place.

For me, that's the key message of this post, and this point is valid in every industry, sector or task at hand.

Produce4• 14 years ago

Best practices are invaluable when used as a guideline. They are abhorrent when used as a rule.

DannoHung• 14 years ago

God I hate JavaScript. It's the C++ of the new millenium. 10 gallons of shit in a 5 gallon hat. Dominant only because of switching costs.

Fuck Javascript. Good parts be damned.

lowboy• 14 years ago

Good for you, stay away from it. One less half-assed js developer in the world.

Isofarro3• 14 years ago

;

Best practice is about a practice that helps create maintainable code. Code is maintained by people. So a best practice is really about getting the best code delivered by the people you have in the most appropriate time possible, and code that can be maintained by those same group of people and others who may be brought into the project at a later date.

Insisting on semicolons means that the bar to entry for being able to develop and maintain a JavaScript code base is lower. Also, we can spend more time thinking about the purpose of the code rather than it's syntax. That helps when it comes to debugging, spending more time thinking about what the code is trying to do rather than losing time figuring out whether the syntax without semicolons is causing an unintended side effect.

The lack of semicolons argument reminds me of the Python versus Java argument. Choosing python gives you a much smaller range of people who could work on your project, but on average the quality of that developer would be better than if you opted for Java.

The advantage of the non-semicolon stance is that they are increasing the minimum level of competancy before someone can work on their project. The disadvantage of the non-semicolon stance is that they are increasing the minimum level of competancy before someone can work on their project.

ZenPsycho• 14 years ago

Having too many semicolons will never ever cause you a problem. Having too few almost certainly will. Why is this an argument? Don't we have enough bugs to deal with? just use the semicolons, or get out of my way.

Most arguments about style are almost certainly pointless, but if you are faced with a choice between two styles, one of which may cause a problem sometimes if you don't know what you are doing, and the other style, which will never ever cause you a problem, it seems the choice is kind of obvious, no? Particularly since the guy doesn't really make a case for what his objection to semicolons actually is to begin with. He doesn't like the look of them?

Best Practices Exist For A Reason

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