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PavlovsCat
I thank you from the bottom of my heart. This drove me crazy when playing around with WebGL and shaders, because for various reasons I didn't want to put those in separate files.
waynecochran
Why aren't you just doing this, for example?

        <script id="fragment" type="x-shader">
	precision highp float;
	uniform vec3 glyphColor;
	void main() {
	        gl_FragColor = vec4(glyphColor, 1.0);
	}
	</script>
PavlovsCat
Because you can't do that from within javascript, and my HTML was really just a stub to load all the javascript I didn't want to have to otherwise deal with.
martin-adams
Interesting solution. I usually find this type of problem when doing templating in the client when updating things via Ajax. I either use the DOM to store the template or end up concatenating for smaller things.

Since to preserve these comments in minification requires conscious effort, I wonder if there's an alternative that could convert the comments to regular JS before minification. Obviously you can't just run it in Node as normal doing it this way.

mappum
That's a really smart hack, I didn't realize comments were included in the output of Function#toString. You could do other cool things, e.g. an annotation for type checking:

  function checkType(f) {
    return function(a) {
      var type = f.toString().match(/\/\/(.*)\n/)[1].trim();
      if(type !== typeof(a)) throw new Error('Invalid type');
      return f(a);
    }
  }
  
  var halve = checkType(function(n) {
    // number
    return n / 2;
  });
  
  halve(4); // returns 2
  halve('string'); // emits error
tlrobinson
I didn't realize comments were included in the output of Function#toString

Probably because sometimes they're not, depending on the JavaScript engine (though perhaps all of the major modern browsers do)

mofle
The following browsers return comments:

- Latest Chrome

- Firefox >=17

- Safari >=4

- Opera >=9

- Internet Explorer >=6

From: https://github.com/sindresorhus/multiline#compatibility

coldtea
Not just "Latest Chrome". Chrome has been doing it for at least 2 years. I know, because I'm using it with it.
manojlds
I think Chrome is mentioned as "Latest Chrome" because:

1) There have been so many versions and not easy to know what came when.

2) Most people get updated to Chrome latest automatically without any fuss.

mofle
That's correct. Chrome is practically versionless.
igl
Closure Compiler.
chrishawes
This is really handy for DFP creative templates. Thank you.
adrusi
When I was first really to program I was into hacking javascript to do the crazy things I wanted it to do. I basically did exactly this, albeit with a worse interpolation feature[1]. Don't actually do this please. In the browser, just open up a different <script type="text/plain"> and grab the string from that tag. On the server you can just use a file. Any string that's actually long enough for `["foo", "bar"].join("\n")` to be too cumbersome should be in a separate file, especially if the other way involves a massive hack.

[1]: http://zurb.com/forrst/posts/Javascript_native_multi_line_st...

jonpacker
So you would suggest using external text files to store every SQL/Cypher query that is used in a model-based node app?
adrusi
Well, if the query is longer than a 3-4 lines then it's really a program in its own right, and yes, I think it deserves its own file.
igl
I think i saw 8 libraries before who abused comments like this.

Edit: Yawn.

wldlyinaccurate
Probably worth pointing out that this won't play nice with most minification utilities unless you don't mind leaving all comments in the output.

I think for this reason I still prefer using Array.prototype.join for multiline strings:

    var str = [
        '<!doctype html>',
        '<html>',
            '<body>',
                '<h1>❤ unicorns</h1>',
            '</body>',
        '</html>',
    ].join('');
gravity13
You can also

  var str = ' \
      <!doctype html> \
      <html> \
        <body> \
          <h1>❤ unicorns</h1> \
        </body> \
      </html> \
  '
I find it's better than string concat because the trailing \ is just one annoying thing rather than three.
tekacs
... also this is (presumably) 'joined' at parse time, rather than runtime (and so only once per execution, guaranteed).
jaredmcateer
6 months later:

    var str = ' \
        <!doctype html> \
        <html> \
          <body> \ 
            <h1>❤ unicorns</h1> \
          </body> \
        </html> \
    '
Help I'm maintaining your code and I get a syntax error
jasonkostempski
HA! I (don't) see what you did there :)
msujaws
There is a space following one of the slashes.
andrey-p
Ooh I really really like this. Preserving newlines (one of the stated usecases for multiline) is dead easy too.

  var str = [
    //...
  ].join("\n");
tlrobinson
FYI, CoffeeScript has multiline strings (and a bunch of other nice things!)
mushishi
Sorry but what does this have to do with anything?
tlrobinson
If you want niceties like multiline strings, CoffeeScript is a better option than clever hacks like this.

    var str = multiline(function(){/*!@preserve
    multi
    line
    string
    */console.log});
Really?
mushishi
Well, I don't get what is the point of suggesting alternative languages that have multiline strings when we are talking about one specific language.

The topic is about how to do multiline string in Javascript in one way, and one alternative is not to use multiline strings in Javascript. It's kinda big jump from the original purpose of the topic to start suggesting alternative languages... if we are to be this slack, then we can start spamming most threads with weakly related stuff. For example, you can easily advertise coffeescript in each and every javascript thread in a similar way you did in this specific thread but do we really need want that?

asdfologist
I do. I love learning about closely related topics while reading the comments.
nottombrown
Coffeescript is just javascript with syntactic sugar on top. This library provides sugar for multiline strings.
idlewan
To me, this library tastes more like too much salt.
coldtea
So, a transpiler, with new syntax, and its own set of BS issues, including an added step in your JS workflow (for the transpiling), is better than a small library doing exactly what you want?
andrelaszlo
This snippet does the same thing, mostly:

    var multiline = function(){/*
    foo
    bar
    baz
    */}.toSource().match(/\/\*([\s\S]*)\*\//)[1].trim()
mofle
Yeah, pretty much, but in Node we wrap repetitive things in modules, as they're super cheap. Your snippet is also missing some things like indentation stripping, error handling and browser support.
dsego
Why not a pre-processor?
mofle
In Node.js you don't want a compile step. In the browser however that would probably be a better solution indeed.
alextgordon
Why don't you want a compile step?
mofle
Because a compile step is annoying when it's not strictly needed. In the browser you usually have some kind of build system for concatenation and minifying anyways.
knubie
With coffeescript, at least, there is no extra compile step from the user's point of view. You can run `coffee myapp.coffee` in the same way you would run `node myapp.js`
aikah
no compile step needed in nodejs. Most third party languages can hack require so using the transpiled language requires no manual compilation.
evilpie
>Note that ES6 will have template string which can be multiline, but time...

Firefox Nightly currently supports just enough of template strings to give you multiline strings.

teddyh
Today I learned that in JavaScript, comments are significant and part of the code.

(And people complain about Python having significant whitespace?)

Kiro
Only significant if you want it to be.
cyphunk
seriously? you people be nuts

    http://stackoverflow.com/a/15558082/2371924
    var myString = function(){/*
      multi-line
      string
    */}.toString().slice(14,-3)
take this code snippet, throw a package.json and some yaml in and make another npm to Show HN.
coldtea
Yeah, only it does several other things do. Like optionally removing indend whitespace.

Did you even read TFA?

ricardobeat
Be sure to scroll to the bottom for a real-world example, this is very brittle.
jgillich
I just use ES6 template strings together with the es6ify transform for Browserify. Works in all browsers and very likely performs much better than using Function.prototype.toString.
mattdesl
Cool hack, but a cleaner solution would be to just use fs.readFileSync if you really want long strings, and let browserify/brfs to inline it for you in the browser.

Using this in a library would be pretty unsafe, given how it's browser-dependent, is prone to issues with minifcation, and could just break with future versions of your JS engine.

VeejayRampay
In other news, the ubiquitous language of the ubiquitous platform of the information age doesn't support multiline strings. But I guess if we keep throwing enough modules and libraries at it, it'll end up being nice to develop for.

Alternatively wait for ES6 or ES7 to (maybe) solve the problem.

[deleted]
(comment deleted)
tfb
Weird... I just just randomly looking at this a few days ago upon a search for "js multiline" when wondering about the common way to spell multiline (multi line vs multi-line vs multiline). I was intrigued by his code though, ultimately in awe of the cleverness and conciseness of it. Very cool hack! Crazy coincidence to see the very code on HN only a few days later.
jasonkostempski
Cool hack but not supporting multiline strings is a feature as far as I'm concerned. Everyone seems to agree that HTML shouldn't contain JavaScript, why should JavaScript contain HTML?
biscarch
That is actually currently being contested by React and .jsx.

That said, I've seen multiline abused for writing SQL queries as well, which would have been better off being written in a separate .SQL file and `fs.read` into a string with a descriptive var name. (Ignoring that massive SQL strings is a code smell imo).

siculars
Except if your application generates dynamic queries. And not of the sort where variables in the WHERE clause are dynamically evaluated. Of the sort where the entire structure of your SQL is dynamically driven by user interaction with your application.
biscarch
Are you saying that large SQL strings isn't a code smell if the application is dynamically putting them together? That seems like DSL/Query Builder territory to me. Perhaps you could share an example?
eob
At one point the E4X standard (back in 2007?) enabled a cool multi-line string hack by promoting XML elements to language entities. You could say:

    var htmlFragment = "" + (<r><![CDATA[
    l(a
    
    le
    af
    fa
    
    ll
    
    s)
    one
    l
    
    iness
    
    - e.e. cummings
    ;
    ]]></r>);
And then `htmlFragment` would contain your multi-line string. (The addition with the empty string coerces the <r> element to output its `toString()` value, which happens to be the innerHTML).

This is largely a historical factoid, though. I don't think browsers beyond Mozilla ended up supporting E4X.

Really clever hack with the function's toString method!

tach4n
Wouldn't something like a Sweet.js macro be better for this? Just have it output a string with '\n\' at the end of lines, or using Array.join() or whatever you like.
robgibbons
This is a very clever hack. Great use of anonymous functions and toString.