# multiline [](https://travis-ci.org/sindresorhus/multiline)
> Multiline strings in JavaScript
No more string concatenation or array join!
*Note that ES6 will have [template string](http://www.2ality.com/2011/09/quasi-literals.html) which can be multiline, but time...*
#### Before
```js
var str = '' +
'' +
'' +
' ' +
' ❤ unicorns
' +
' ' +
'' +
'';
```
#### After
```js
var str = multiline(function(){/*
❤ unicorns
*/});
```
## How
It works by wrapping the text in a block comment, anonymous function, and a function call. The anonymous function is passed into the function call and the contents of the comment extracted.
Even though it's [slower than string concat](http://jsperf.com/multiline), that shouldn't realistically matter as you can still do 2 million of those a second. Convenience over micro performance always.
## Install
```sh
$ npm install --save multiline
```
## Usage
Everything after the first newline and before the last will be returned as seen below:
```js
var str = multiline(function(){/*
❤ unicorns
*/});
```
Which outputs:
```
❤ unicorns
```
### Strip indent
You can use `multiline.stripIndent()` to be able to indent your multiline string without preserving the redundant leading whitespace.
```js
var str = multiline.stripIndent(function(){/*
❤ unicorns
*/});
```
Which outputs:
```
❤ unicorns
```
### String substitution
`console.log()` supports [string substitution](http://nodejs.org/docs/latest/api/console.html#console_console_log_data):
```js
var str = 'unicorns';
console.log(multiline(function(){/*
I love %s
*/}), str);
//=> I love unicorns
```
## Use cases
- [CLI help output](https://github.com/sindresorhus/pageres/blob/cb85922dec2b962c7b45484023c9ba43a9abf6bd/cli.js#L14-L33)
- [Test fixtures](https://twitter.com/TooTallNate/status/465392558000984064)
- [Queries](https://github.com/freethejazz/twitter-to-neo4j/blob/a41b6c2e8480d4b9943640a8aa4b6976f07083bf/cypher/queries.js#L15-L22) - *here an example in Cypher, the query language for Neo4j*
- [CLI welcome message](https://github.com/yeoman/generator-jquery/blob/4b532843663e4b5ce7d433d351e0a78dcf2b1e20/app/index.js#L28-L40) - *here in a Yeoman generator*
Have one? [Let me know.](https://github.com/sindresorhus/multiline/issues/new)
## Experiment
I've also done an [experiment](experiment.js) where you don't need the anonymous function. It's too fragile and slow to be practical though.
It generates a callstack and extracts the contents of the comment in the function call.
```js
var str = multiline(/*
❤ unicorns
*/);
```
## FAQ
### But JS already has multiline strings with `\`?
```js
var str = 'foo\
bar';
```
This is not a multiline string. It's line-continuation. It doesn't preserve newlines, which is the main reason for wanting multiline strings.
You would need to do the following:
```js
var str = 'foo\n\
bar';
```
But then you could just as well concatenate:
```js
var str = 'foo\n' +
'bar';
```
*Note that ES6 will have real [multiline strings](https://github.com/lukehoban/es6features#template-strings).*
## Browser
While it does work fine in the browser, it's mainly intended for use in Node.js. Use at your own risk.
### Install
```sh
$ npm install --save multiline
```
*(with [Browserify](http://browserify.org))*
```sh
$ bower install --save multiline
```
### Compatibility
- Latest Chrome
- Firefox >=17
- Safari >=4
- Opera >=9
- Internet Explorer >=6
### Minification
Even though minifiers strip comments by default there are ways to preserve them:
- Uglify: Use `/*@preserve` instead of `/*` and enable the `comments` option
- Closure Compiler: Use `/*@preserve` instead of `/*`
- YUI Compressor: Use `/*!` instead of `/*`
You also need to add `console.log` after the comment so it's not removed as dead-code.
The final result would be:
```js
var str = multiline(function(){/*!@preserve
❤ unicorns
*/console.log});
```
## License
MIT © [Sindre Sorhus](http://sindresorhus.com)