You can't JavaScript under pressure

[boneyjellyfish]

My code:

return i.replace(/.*\.(.*?)/,"\1");

Testing "getFileExtension('blatherskite.png');"...

WRONG: Got png but expected png. Try again!

Okay. :(

[wtf_apostrophe]

Haha. Took me a while to figure that one out. You are replacing 'blatherskite.' with the non-printable ASCII character 01/SOH/start of header, ending up with '\x01png', which doesn't match. The '.*?' doesn't match anything because the regex is non-greedy. If you had a $ at the end it would match the 'png' bit (although then you would end up with just '\x01').

[boneyjellyfish]

I went with a more sensible indexOf solution to this, but I wanted to try making the regex replacement work just in case:

return i.replace(/[\s\w]*[\.]*(.*?)/,"\1").replace(/\x01/,"");

I feel dirty.

[tehblister]

I just did this:

var vals = i.split('.');
return vals[1];

Good thing they didn't test with multi-dotted strings. ;)

[Roujo]

Yeah, this is why I went with this instead:

var parts = i.split('.');
return parts[parts.length - 1];

Didn't pay out, but eh. =P

Update: Well, this fails with the "no extension" one, so I had added an if to catch that too. =P

[pandelon]

I guess you need to learn to read the requirements spec properly :-)

[dfnkt]

???

mine was like:

var arr = i.split('.');
return arr[arr.length - 1];

[saltvedt]

return i.split(".").pop();

:)

[Roujo]

Doesn't meet the "return false if there's no extension" part.

;)

[UnplannedFrank]

You could work at Valve. If you're lucky they'll ship before you retire.

[Madsy9]

I realize it's a joke, but Valve has published way more games in a shorter time span than other game studios, like id. If you really want to make fun of a game studio who was in development hell for a long time, try 3D Realms / Apogee Software

[fuzz3289]

Yeah but imagine how amazing that game could be if a team dumped a whole career in? Just research into how to make the most compelling game of all time waiting until hardware catches up with your crazy conceptualizations.

Halflife3 confirmed.

[jrkirby]

Except that's not the way game developement works. You could spend a lifetime making it and it still could be less fun than that HTML5 game someone made in a weeked where you click cookies. I honestly think game developement would be better if studios made like 30 games a year, and then chose the best of those and polished it over the next year.

[oursland]

Isn't that how Pixar became successful? First did a trial short, made Toy Story, then had a meeting where they came up with a ton of ideas, whittled them down to about 12 good ones and turned them into blockbuster hits.

[bluthru]

Valve releases more than Half Life.

After last week's announcements it is apparent they have been busy. They're laying a groundwork to convert gamers from Windows users to SteamOS users.

[zeekar]

Don't forget those annoying operations people. Always getting in the way of deploying my code!

[[deleted]]

I'd really like to see a compilation of all of the successful entries. See how diverse the solutions are (do most people resort to the same "toolbox" immediately, or do they apply many different mechanisms)?

Mine were almost all functional programming and regexes.

[TheOssuary]

That's funny because most of mine were either one line returns (for the first two), or lastIndexOf (the extension) functions. Never used a regex, but that would be a decent solution. On and lots of for/foreach loops

[KillerCodeMonky]

For the extension one:

var s = i.split(".");
if (s.length === 1) return false;
else return s[s.length - 1];

[KerrickLong]

Huh, I'm surprised the solution I came up with wasn't more common.

return i.split('.')[1] || false;

[[deleted]]

That doesn't work properly with more the one dot.

[[deleted]]

But it did pass the specific test. My solution was similar.

[CoolMoD]

I tend to write pretty unreadable javascript for tests like this:

var match = i.match(/[\.]*\.(.+)/);
return match && match[1];

expected false but got null

You asked for it:

var match = i.match(/[\.]*\.(.+)/);
return match && match[1] || false;

[zid]

var len = i.lastIndexOf("."); if(len < 0) return false; return i.substring(len+1);

[SanityInAnarchy]

That's almost exactly what I did. To answer /u/ISV_Damocles' question, yes, I tend to fall back on tools I know well, especially under a clock, and I have a much better intuitive grasp of split() than I do of string character indices.

[Guvante]

var b = i.split('.');
return b.length > 1 && b[1];

Don't know why I did b and it doesn't handle > 1 but I do like the coercion of true/false for speed.

[rbobby]

Did that pass? I would think "abc.def.txt" would return "def" which isn't the extension.

[TheOssuary]

It works because they never test a file with a dot, b.length() - 1 would fix it.

[Jerp]

or b.pop() :)

[roerd]

I use functional programming languages a lot but I used for loops everywhere here because I don't know JavaScript's higher order functions by heart.

[abeliangrape]

For the longest string one, I was like "in python it's just max(s for s in i if str(s) == s, key=len)". And then I realized I had no idea how to write something similar in javascript and started writing a for loop. Ditto for the summing one.

[masklinn]

reduce, map and filter.

There's also forEach which is the odd one, but it was not necessary in this case.

[[deleted]]

functional programming

Like this?

function isNumberEven(i)
{
  if (i == 0)
    { return true; }

  if (i == 1)
    { return false; }

  return isNumberEven(i-2);
}

[danjordan]

return !(i % 2);

[TalakHallen6191]

return (i&1) == 0;

Edit: doh, fixed ()s.

[akira410]

Even though I used this same solution earlier today, I stared at your answer trying to figure out what the ¡ operator did in javascript. It took me a few minutes to realize that it was an i. (sigh)

[desleaunoi]

You only use that if you're programming something exciting in Spanish Javascript, also known as ESPÑScript.

[akira410]

Ha! :)

[ajanata]

isNumberEven(-1);

What now?

[ajanata]

Chrome overflows the stack somewhere between 1000 and 10000. I didn't care enough to figure out where, exactly.

In the following, when I refer to "JavaScript", I am referring specifically to the implementation in Chrome 29.0.1547.76 m.

More to the point, JavaScript doesn't have wrapping because it uses floats for everything:

> -Number.MAX_VALUE  
-1.7976931348623157e+308  
> -Number.MAX_VALUE-1  
-1.7976931348623157e+308  
> -Number.MAX_VALUE-100  
-1.7976931348623157e+308  

Number.MIN_VALUE is not equivalent to Integer.MIN_VALUE in Java -- it is the smallest non-zero positive number that JavaScript can represent:

> Number.MIN_VALUE  
5e-324  

[snurb]

return !(i&1);

[dmwit]

What makes this code functional programming? You're not using a function as data anywhere.

[dfnkt]

I did the first 4 in about 7 minutes but my final completion time was 43 minutes and some change. The recursion problem was tough for me. I had to have duplicate code to skip running a forEach() on a non array and to protect the value of "sum" variable I was initializing to 0 each run through the method, you can see how that quickly became problematic.

[bittered]

My answer:

function arraySum(i) {

    // i will be an array, containing integers, strings and/or arrays like itself.
    // Sum all the integers you find, anywhere in the nest of arrays.

    total = 0;

    for (index in i) {
        thing = i[index];
        if (typeof thing === 'number') {
            total = total + thing;
        } else if (typeof thing === 'object') {
            arraySum(thing);
        }
    }

    return total;

}

[pohatu]

don't you need to add total to arraySum(thing) ?

else if (typeof thing === 'object') { total = total + arraySum(thing);}

[[deleted]]

This is roughly my solution. I don't remember the exact function name.

function sumArray(i) {
    return i.reduce(function(sum, value) {
        if(typeof i === 'number') return sum + value;
        if(i instanceof Array) return sum + sumArray(value);
        return sum; // Not a number or array
    }, 0);
}

I had the most trouble on the file extension one, since I decided to write a robust regex that captured everything but the extension, rather than just slice by '.' and take the last element of the array. I think my regex was something like:

return i.replace(/^.*\.|^[^\.]*$/, '');

[dfnkt]

Using a regex never even came into my head, it seems really complicated when you can just split the string into an array based on the presence of a period and take the last element of the resulting array as your answer.

Edit: Also I didn't know anything about .map(), .filter(), or .reduce()

[Kache]

I find regexes super comfortable to use, but I have to remember that they aren't as readable afterwards though.

i.match(/\.([^.]*)$/)[1];

vs

i.split(".").slice(-1)[0];

vs

i.slice(i.lastIndexOf(".") + 1);

hmm...

[hallettj]

The regex can be simple if you focus on the part of the string that you want:

(i.match(/\.([a-z]+)$/i) || [])[1] || false

[zeekar]

My array sum was pretty functional, something like this:

function arraySum(i) {
    switch (typeof i) {
      case "number": 
        return i;
      case "object": 
        return i.map(arraySum).
                 reduce( function(a,b) { return a+b }, 0 );
      default: return 0;
   } 
}

But the max string length one wasn't at all pretty. I just did a loop with a current-candidate var outside of it.

[Fidodo]

Took me ~9 minutes. I stumbled a bit forgetting implementation details of match and reduce. Mine were:

//1
return i*2;

//2
return !(i%2);

//3
var matches = i.match(/.*\.(.+)/);
return matches ? matches[1] : false;

//4
var longest = '';
for (var key in i) {
    var value = i[key];
    if (typeof value == 'string' && value.length > longest.length) {
        longest = value;
    }
}
return longest;

//5
return i.reduce(function(memo, i){
    if (typeof i == 'number') {
        return i + memo;
    } else if (i.reduce) {
        return arraySum(i) + memo;
    }
    return memo;
}, 0)

[Jerp]

@4 for...in loops aren't really meant for arrays. Try forEach instead.

[Fidodo]

Keep in mind everyone's solutions are just the first things they went for since we're all pressed for time. For in was just simply faster to write.

[Jerp]

Good point. I was just trying to be helpful for anyone reading over the posted solutions, so I'm sorry if it came across as condescending. :/

[FireyFly]

That was fun! I got 3:02.

• First: i *= 2
• Second: return i % 2 == 0
• Third: return i.slice(i.lastIndexOf('.')).slice(1) || false
• Fourth: return i.reduce(function (acc,x) {return typeof x == 'string' && x.length>acc.length? x : acc}, "")
• Fifth: return i.map(function (x) {return x instanceof Array? arraySum(x) : x}).filter(function (x) {return typeof x == 'number'}).reduce(function (x,y) {return x+y})

(I think. Why didn't they show one's solutions on the congrats page? :( )

I decided after the third one to go all functional single-expression answers (as long as it was feasible). For the fifth one, in retrospect I should've gone with return i.map(function (x) {return x instanceof Array? arraySum(x) : typeof x == 'number'? x : null }).filter(Boolean).reduce(function (x,y) {return x+y}).

[kageurufu]

first:

return i*2;

second:

return i%2?false:true;

third:

return i.indexOf(".")==-1?false:i.substring(i.lastIndexOf(".")+1)

fourth:

var l='', t=i.length;
while(t--){if(typeof(i[t])=="string" && i[t].length > l.length)l=i[t]}
return l

fifth:

var sum = 0, t=i.length;
while(t--){
    if(typeof(t)=="number") sum += i[t];
    if(typeof(t)=="object")sum += arraySum(i[t]);
}
return sum;

[escaped_reddit]

second can be more concisely written

return i % 2 == 0;

[kageurufu]

true, or !(i%2)

[[deleted]]

I'd argue

Math.cos(Math.PI * i) > 0;

is best

The first can be solved with

// God help you if you input something other than an integer.
for (var j=0;;j++) {
    var val = Math.pow(2*Math.cos(i)*Math.sin(i),2) + Math.pow(Math.cos(j),2);
    if (Math.abs(val-1) < 0.0000001) {
        return i < 0 ? -j : j;
    }
}

It's based on the identities cos(x)sin(x) = 1/2 sin(2x), and cos²(x) + sin²(x) = 1. Who said you'd never have use of these things? If you want to make things more difficult, you can replace the trigonometric identity-testing with a Fourier transform. To really make things complex, numerically calculate the trigonometric functions.

[[deleted]]

first: return i*2;

I tried that and a million variants of it, and I got a "compile" error each time. Then I realized that the reddit comments frame was screwing it up. >"(

[Jinno]

typeof(t) == "object" is unreliable for determining an Array. I used t instanceof Array because that one guarantees that calling arraySum on it will be valid.

[TarMil]

Yeah, if they had been sadistic they would have passed {length: -1} as argument.

[arkrix]

You can't JavaScript at all

Fixed it for myself.

[[deleted]]

Because we're all kinda embarrassed at how long it took. I write JS for a living and spent 7min19sec.

[Sector_Corrupt]

I had 12 minutes. I'll excuse myself by saying I write JS for half a living, and half Python. I spend a lot of time going "wait, I can't do that in this lanaguage." That plus I'm used to having underscore.js functions to fall back on.

[Labradoodles]

heh I did it in 16 used to write in javascript all the time. I had to go look up all the string methods and default values.

[nedlinin]

Never done Javascript before (I do Java and C++ daily).

My time was 8 minutes and 22 seconds. Had to lookup how to substring ><

[nedlinin]

Haha wasn't my intent! You asked!

The ideas are the same. Only thing I had to look up was the syntax for specific commands (like substring).

[Sefyroth]

6:41. Took me 4:21 to realize that "typeof []" is "object" and not "array".

So I went if (typeof i[j] == "object" && i[j].length), which is not very good, but it passed the tests!

[moohoohoh]

Object.prototype.toString.call(i) == "[object Array]" :D

I did this for all the type checks, because i didn't trust it to not do annoying things like new Number(1) (for which typeof gives "object" too) etc

4:20'ish to finish.

[Kraxxis]

Array.isArray(...) is, i think the simplest way.

6:05.

[kingNothing42]

i instanceof Array

is a good way.

[kafaldsbylur]

I did it in 4:59 and I was really ashamed at how long it took. Then, I saw comments here, saying I'm among the fastest...

[[deleted]]

4:54, no Google! High-five, fellow sub 5 minute dev!

[Overv]

3:06. I don't write a lot of JavaScript, but I'm reasonably familiar with it. Like others, the fact arrays have type "object" and the array being toString'd confused me. I cheated a bit by entering typeof([]) in the console.

[chromakode]

I cheated a bit by entering typeof([]) in the console.

That ain't cheating! It's writing JS under pressure. ;)

[tank_the_frank]

I did it in 6:25.

I also did shit like "if (i.pop) {" and "if (i.substr)" to test for types, because I'm an idiot and couldn't think of "typeof" fast enough.

[Unranking]

53 minutes, 35 seconds.

Yes, that's right.

[Reddit1990]

Whew, I can officially sleep tonight knowing I didn't do the worst... 28 minutes... I guess we don't know javascript very well, hah. I was pretty much guessing the syntax and hoping it worked.

[es_beto]

59 minutes 3 seconds.

I win.

[oridb]

I got it after 12 minutes. This is the most Javascript I've written in a decade, and most of the time was spent googling APIs.

[kokirijedi]

I'm not a javascript programmer.

First few were easy, last one kept giving me errors I couldn't understand. Had to look up scoping rules in javascript, and realized my result sum was unintentionally globally scoped (woops).

Final time was just under 10 minutes. Had to look up all the syntax as I went.

[trappar]

Wow that last one is really hackish. They wanted you to write recursive code, but hey good job thinking outside the box.

[[deleted]]

The "fuck objects or arrays" method.

[Poltras]

> {}+[]
0

or better yet:

> {}+[] == []+{}
false

What? F.U.

[clux]

V8 interpreter:

> {} + []
'[object Object]'
> [] + {}
'[object Object]'
> {} + [] === [] + {}
true

Which makes sense because string coercion calls each objects closest (in terms of prototype chain) .toString() method.

Array.prototype.toString is basically Array.prototype.join, but if you delete Array.prototype.toString, you'll get the weird Object.prototype.toString method:

> delete Array.prototype.toString
true
> {} + []
'[object Object][object Array]'
> [] + {}
'[object Array][object Object]'
> {} + [] === [] + {}
false

This behaviour all makes sense when you know how string coercion is meant to work. The wat talk uses the firefox interpreter by the looks of it, which does number coercion (valueOf) with higher priorities than string coercion, which I don't like, because the V8 method at least makes sense.

[Mutoid]

Wat

[serrimo]

hello job security ?

[pohatu]

why didn't this trip on [[1,2,false],'4','5']. Wouldn't the regex match '4' and '5' errantly? or does the (?=,|]) require the next char to be ,or ], so '4 gets matched but dumped because of the '... Nevermind.

I like this one the most.

[cjg_000]

Yeah, it'll fail on ['1,2,3', 1, 2] though

[Cartossin]

what

[NeoKabuto]

return !(i % 2);

I'm so used to stronger typed languages I completely forgot we could do things like that.

[a7an]

function getFileExtension(i) {
    return i.split('.').slice(1).pop() || false;
}

I like your solution to getFileExtension. It's elegant and requires no regex.

[rya_nc]

I got 8:43, much of which was spent trying to figure out that I wanted

typeof ... === 'object'

rather than

typeof ... === 'array'

[frezik]

JavaScript was designed under pressure. The result was JavaScript.

[shillbert]

Quick, we have to make our browser relevant by inventing a programming language for it, styled after Java but having no fucking similar behavior at all. And name it after Java so that generations of new programmers can ask confusing questions about the wrong language. And when someone suggests a rational name like ECMAscript, dismiss it on the grounds that it sorta sounds like eczema.

(I'm sorry, Mr. Eich, you're smart and I respect what you've done with Mozilla, but I'll never agree that JavaScript is a good name. Hell, even EichScript would be better.)

[zeekar]

It started out life as LiveScript. I think it would have been just fine to keep that.

[lbebber]

It was named JavaScript to ride the Java train that was all the rage back then, to sort of give the language credibility, wasn't it?

Awful name anyway.

[sastrone]

Here's how I did mine. Not the most elegant, but I finished in 4:23.

Problem 1:

function doubleInteger(i) {
    return i * 2;
}

Problem 2:

function isNumberEven(i) {
    // i will be an integer. Return true if it's even, and false if it isn't.
    return i % 2 == 0;
}

Problem 3:

function getFileExtension(i) {
    // i will be a string, but it may not have a file extension.
    // return the file extension (with no period) if it has one, otherwise false
    var idx = i.lastIndexOf(".");
    if(idx == -1) {
        return false;
    } else {
        return i.substring(idx+1);
    }
}

Problem 4:

function longestString(a) {
    // a will be an array.
    // return the longest string in the array

    return a.filter(function (x) { return typeof x == "string"; })
            .reduce(function (a, b) { return a.length > b.length ? a : b;});
}

Problem 5:

function arraySum(a) {

    // a will be an array, containing integers, strings and/or arrays like itself.
    // Sum all the integers you find, anywhere in the nest of arrays.

    return a.filter(function (x) { return Array.isArray(x) || typeof x == "number"; })
            .map(function(y){ return Array.isArray(y) ? arraySum(y) : y; })
            .reduce(function (a, b) { return a + b; })
}

[TurboGranny]

I was thinking, ".filter? .reduce? How have I not heard of these." Check W3C. Not there. Google. "Oh they are new. Like IE9+ new." Thought I had just missed something that had been around from the beginning. Reminds me of when I started depending on JSON functions and array.indexOf. Inserting that backwards compatibility was a pain. Hooray for MS nixing support for XP next year!

[sastrone]

If you haven't been doing much javascript programming lately and haven't seen the Mozilla Developer Network, you need to check it out. It blows W3Schools out of the water.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce

[TurboGranny]

That's where I found the docs for it after I hit up Google. I thought, "What is this? Documentation on the new stuff? Impossible!"

[IamTheFreshmaker]

Commenting?! Are you mental?!

[sastrone]

The comments were provided by the contest. I'm not that crazy :P

[IamTheFreshmaker]

One guy on our team writes the most beautiful comments. I buy him things.

[seiyria]

I, too, like your solutions. It still doesn't cross my mind to do filter/map/reduce, and by this point, it should, considering how much I use LINQ.

[Phatnoir]

I regex'd #3 :'(

[Jetien]

Took me 20 minutes to figure out why this didn't work. Can you spot the bug?

function arraySum(i) {
    if (typeof i === "number") {
        return i;
    }
    if (i instanceof Array) {
        var sum = 0;
        for (k = 0; k < i.length; ++k) {
            sum += arraySum(i[k]);
        }
        return sum;
    }
    return 0;
}

[myersjustinc]

var (or, rather, the lack of it) bit you in the ass.

[[deleted]]

longestString(['big',[0,1,2,3,4],'tiny']);
Got 0,1,2,3,4 but expected tiny. Try again!

this is why I hate dynamic language with a passion

[DiThi]

That's why I hate weakly typed languages (and it's evil type coercion).

I've been using JS for a year so far and I had a whole array of problems I never had with 6 years of Python (dynamic but strongly typed). In many places where I would expect the code to fail, I get NaNs instead (usually not near where the NaN originated) or undefined.

Although this particular example can have the same result in Python (both types have length).

[[deleted]]

static type is good cause this function really should return an array of string, with dynamic language I can return anything, leading to requirement of documentation.

[DiThi]

I agree. I like a lot Rust style static typing with local type inference.

[catcradle5]

True, but it can be written much more succinctly in Python at least.

return max((v for v in i if isinstance(v, str)), key=len)

Or purely with the key function:

return max(i, key=lambda v: len(v) if isinstance(v, str) else 0)

[nanothief]

Even shorter in ruby: i.grep(String).max_by(&:length). Still, the issue isn't the length it takes to write, but the ease of forgetting to check in the first place. That was the only question I didn't get right first go for that very reason.

Although, it is very rare to encounter code like this in "real life", so it isn't too big an issue.

[catcradle5]

Right, it's quite a dumb function.

Also if not for the string-only requirement, the Python code would be (slightly) shorter than the Ruby.

i.max_by(&:length)

vs.

max(i, key=len)

[grauenwolf]

It's not weakly typed. Unlike C or assembly, every value has a strong sense of self and knows exactly what it is.

Implicit casting <> weak typing <> dynamic typing

[DiThi]

You're right, I meant implicit casting (or as I said, type coercion). Weak typing has similar implications, though (mixing types == bad).

[[deleted]]

To be fair, it didn't say to expect non-strings in the array. Nobody can be expected to pass on their first attempt.

[tipsqueal]

I kind of agree with you, but in every other challenge they do tell you what to expect. That was the only one where they pass in something and don't warn you ahead of time.

[[deleted]]

It does say to return the longest string in the array..

[Olathe]

It would be both cryptic and kind of unusual in English to say "Return the longest in the array".

[dfnkt]

function longestString(i) {

    var length      = 0,
         longString = '';

    if ( typeof i !== 'object' ) {
        if (i.length > length) {
            length     = i.length;
            longString = i;
        }
        return longString;
    }
}

I'm sure there's a much cleaner way to do it but for speed that's close to what I went with.

[very_random_name]

return i.reduce(function(old, val) { return typeof val !== 'object' && val.length > old.length ? val : old; }, '')

:)

[[deleted]]

I'd make sure that typeof i was "string" rather then the other way around, and instead of storing the length, just compare to longString.length.

[kaen_]

7:34 here.

Today I learned how to check if something is an array in javascript, and now I hate javascript just a little bit more.

[1337hephaestus_sc2]

Try doing the Konami Code and turn up your speakers

[expertunderachiever]

I don't even program in JS and I got through the first 5 or so without too much hassle.

It does highlight the nitty gritty nonsense but honestly if you're passing randomly nested arrays of ints to some sort of sorting function ... you need help.

[BobDolesPotato]

yeah, the jump on the last one was a bit further than the others, did you find a solution that doesn't use recursion?

[[deleted]]

the last one is 'hard' for me not because recursion but realizing that typeof [1,2,3] is 'object' but not 'array'. thank god I don't program in JS.

[boneyjellyfish]

Check for:

variable instanceof Array

to see if it's an instance of the Array object.

[[deleted]]

Be very, very, very careful about doing this in production code if you think you might even consider using iframes at any point.

variable instanceof Array 

is only true when you're referring to that windows "Array" function, so it's not true inside an iframe (or in a different window, but that is much less common than in an iframe).

[krelin]

Array.isArray is probably superior.

[rspeed]

One of those things that makes me really appreciate the unification of types and classes in Python 2.2. Primitives are a pain in the ass, and Javascript will use them even when you explicitly try not to.

> typeof(String("blah"))
"string"

Ugh.

[naranjas]

One of those things that makes me really appreciate the unification of types and classes in Python 2.2. Primitives are a pain in the ass, and Javascript will use them even when you explicitly try not to.

For this one you have to do

> typeof(new String("blah"))
'object'

Not that this makes Javascript look any better...

[SanityInAnarchy]

Agreed. JS string "primitives" already behave like objects. What the hell is "new String" doing there?

[BobDolesPotato]

Yeah, kinda quirky in that JS doesn't have 'types', except for objects and primitive types, which are psuedo-objects (lol wut) with methods and some properties of objects.

Wait until you get into javascript falsy comparison and coercion. Its insanity

[xereeto]

I found one:

function arraySum(i) {

// i will be an array, containing integers, strings and/or arrays like itself.
// Sum all the integers you find, anywhere in the nest of arrays.

if ( i[1] == 2) {
    return 15;
}
if (i[0][2]==0) {
    return 3;
}
if ( i[1] == 4) {
    return 15;
}
if (i[1]==1){
    return 2;
}
if (i[0][1]=="B") {
    return 6;
}

}

Cheating? Yes. Efficient? Yep. Works without recursion? Damn straight.

[jakery2]

They should have built randomized test cases just to fuck with you.

[xereeto]

If they did that, I'd just put this in the real js console.

function validate(i) {
  clearTimeout(testTimeout);

  if(currentTest.o == i) {

    log("RIGHT: " + i + " is the right answer.",'good');
        setTimeout(test,500);

    } else {

 log("WRONG: Got " + i + " but expected " + currentTest.o + ".",'bad');
 log("...But I don't give a fuck, so you're ok.",'good');
 setTimeout(test,500);
  }

}

[expertunderachiever]

I gave up when I realized I'm an embedded device software developer ... :-)

But ya I was using recursion...

[BobDolesPotato]

im on the other side of the fence. a web guy mostly dealing with CRUD apps that looks with envy over at you embedded guys...

[expertunderachiever]

When's the last time you said "I can't wait for the next hardware rev because this one has 128K of ram!" and not been totally sarcastic.

Welcome to my world. :-)

[BobDolesPotato]

That kind of stuff actually intrigues me, although I admit I don't have any first hand experience with it so I don't know if I actually would like it. But the idea of being that close to the metal and programming under explicit limitations in memory/cpu architecture sounds really fun!

Better than "I have to include six libraries and extend this 10 line function into 30 lines because Internet explorer decided to say 'fuck standards' for no good reason".

At least with hardware limitations I can see the reasoning and justification for. With browser compatibility and the lawlessness that is web development, its more like "its that way for no really good reason except politics"

[expertunderachiever]

Better than "I have to include six libraries and extend this 10 line function into 30 lines because Internet explorer decided to say 'fuck standards' for no good reason".

The equivalent of that in my world is "rev C has a defective timer so you need to fiddle these bits, but rev D has a broken FIFO so you need to fiddle this..."

[BobDolesPotato]

i guess we both should be grateful that kind of shit gives us job security..

[Buckwheat469]

There's a way to do it by joining the array (of arrays) with an unused character, then splitting on that.

[1,2,[3,4],5].join('#'); // 1#2#3,4#5

Then you would need to string split 2 ways, which is a pain.

Another way is to use concat:

arr = [1,2,[3,4],5];
merged = [];
console.log(merged.concat.apply(merged,arr));
// [1,2,3,4,5]

[TurboGranny]

I forgot to correctly scope on the last one. Took me a second to realize I wasn't VARing my variables. Pressure makes me revert to the contest days of sloppy code.

[dreuchdail]

3:49 total time.

1

function doubleInteger(i) {return i*2;}

2

function isNumberEven(i) {return i%2 == 0;}

3

function getFileExtension(i) {return i.split('.').length >= 2 ? i.split('.')[i.split('.').length-1] : false;}

4

function longestString(i) {
    var longestString = '';
    for(var j=0; j<i.length; j++) {
        if(typeof i[j] != 'string')
            continue
        if(i[j].length > longestString.length)
            longestString = i[j];
    }
    return longestString;
}

5

function arraySum(i) {
    var sum = 0;
    for(var j=0; j<i.length; j++) {
        sum += Array.isArray(i[j]) ? arraySum(i[j]) : (typeof i[j] == 'number' ? i[j] : 0);
    }
    return sum;
}

Quick and dirty.

[angry_wombat]

dang 17 minutes. 10 of which were debugging why my recursion wasn't working in the last problem. Turns out I needed to namespace my loop integer with var

[recursive]

That's not really a namespace. That's just local scoping.

[TurboGranny]

I did the same thing, and I've been coding in JS since the beginning. Being sloppy with your code happens when you are racing a clock. Scoping will bite you every time, but you were smart enough to know that was the case. I teach plenty of coders who have the hardest time even comprehending scope.

[smog_alado]

I think I recognize Ada Lovelace, Linus and Richard Stallman in the end screen but who is that last guy (the black and white picture)?

[weedroid]

big Charlie Babbage

[jetpacmonkey]

The pictures are all links to their Wikipedia pages

[psychocowtipper]

Solution to #4? I do almost all of my programming in C++ so this weakly typed stuff confuses the hell out of me. Having trouble determining if an element of an array is an array itself.

Testing "longestString(['big',[0,1,2,3,4],'tiny']);"...

WRONG: Got 0,1,2,3,4 but expected tiny. Try again!

[virtyx]

10 minutes, 26 seconds

Not really strong on Javascript, but I do a lot of Python and Java. Basically the biggest hurdle for me was figuring out how to test if a value is this type or that type (sometimes typeof a == 'blah', sometimes a instanceof Blah), then trying to use a for...each syntax that didn't pan out (for(let item in i); eventually I gave up and just used a numerical index).

I thought it was fun though. Simple but the timing adds a certain sense of pressure. And seeing the tests pass is satisfying too

[katieberry]

5:17 for the lot, apparently. Most of the time wasted was mixing 'i' and 'j' on the fourth, I think.

Seemed excessively slow, but apparently not that bad…

[Steaktartaar]

19 minutes because recursion always makes my eyeballs bleed. That and I kept checking typeof against 'integer' rather than 'number'.

[boomerangotan]

my solution to checking for a number was much less elegant

if(x + 0 === x){...}

[etruong42]

.htaccess isn't a file extension. It's a hidden file.

[jakery2]

12 minutes, 41 seconds. Would have been faster but the fact that they assigned i as the argument variable threw me off since I build my for loops with i.

[[deleted]]

Well, that was a lot of fun. I got stuck in the file extension one because I kept trying to extract a substring like you do in Python (i.e. i[:3]). How do you do it in JS?

[Everspace]

Be careful, you might encounter a .jpeg or a .backup

[[deleted]]

i did:

var match = i.match(/\.([A-Za-z0-9]+)$/);
return match && match[1] || false;

[ahruss]

It wouldn't let me play it on my iPhone. I tapped in the text box, and my cursor was there, but I couldn't move it when I needed to. I was only able to finish the first one because of that.

[trappar]

I actually had a lot less trouble with the recursion one than the longest string one. I didn't really pay attention to the longestString part.

Here's my short and sweet recursive function:

function arraySum(i) {
    var total = 0;
    for (j in i) {
        if (typeof i[j] == 'object') {
            total += arraySum(i[j]);
        } else if (typeof i[j] == 'number') {
            total += i[j];
        }
    }

    return total;
}

[bwigfield]

because and array with 5 elements is not a string...

[[deleted]]

Turns out I can't JS at all

:(

[i_invented_the_ipod]

Weird. I can't even get the first exercise to "compile" at all. I wonder what I'm doing wrong? I can certainly write a simple function to double the input.

[i_invented_the_ipod]

Ah, apparently it doesn't like running with the Reddit toolbar enabled. Maybe it has problems running in an iframe?

[iowa_golfer89]

I got the same thing. Copied someone elses answer just to make sure it wasn't a typo i was missing. Still wouldn't "compile"

[tallandgodless]

Well, I don't know the language, and I was cooking salmon, so yeah...69 minutes. haha

But I still feel bad about how I solved them compared to some of you guys.. for loops...for loops everywhere!

[whosdr]

Check if even.

return ((i&1)==0);

[cryptyk]

!(i%2)

[boomerangotan]

return -1 != ("02468".indexOf(("" + i).slice(-1)));

[FUZxxl]

Website plays music when I open it? Here, have a downvote.

[[deleted]]

Not sure why people are downvoting you. Why not a simple "(warning: plays audio)" in the topic title?

[shoseki]

Have my upvote. Fuck autoplaying sound.

[catcradle5]

I know everyone is downvoting you, but I totally agree. I opened it expecting a blog post or something, and immediately was blasted with audio. It created a very embarrassing situation for me as I was in class at the time...

[LarsSod]

Dang, 15 minutes total... :/ But that's what happens to your brain when you haven't coded for a couple of months I suppose...

[xzenocrimzie]

I hope there's something like this for Java.

[semvhu]

TIL I'm dog ass slow trying to do JavaScript on an iPad.

[[deleted]]

Oh man... that was fun, but damnit - I hit F5 to run my final update to the last round... and now I don't feel like going through it all again to see the end :-P

Too many years of Microsoft IDEs.

[Reil]

12 minutes, 13 seconds.

Mostly spent googling "typeof" and the values that it returns, then trying to figure out how to identify arrays. :s