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https://github.com/sindresorhus/multiline

Multiline strings in JavaScript
https://github.com/sindresorhus/multiline

deprecated

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Multiline strings in JavaScript

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# multiline [![Build Status](https://travis-ci.org/sindresorhus/multiline.svg?branch=master)](https://travis-ci.org/sindresorhus/multiline)



> Multiline strings in JavaScript



No more string concatenation or array join!



*Use ES2015 [template literals](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/template_strings) instead whenever possible.*



#### Before



```js

const str = '' +

'' +

'' +

'	' +

'		
❤ unicorns
' +

'	' +

'' +

'';

```



#### After



```js

const str = multiline(()=>{/*



	

		
❤ 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



```

$ npm install multiline

```



## Usage



Everything after the first newline and before the last will be returned as seen below:



```js

const str = multiline(()=>{/*



	

		
❤ 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

	const str = multiline.stripIndent(()=>{/*

			

			

				

					
❤ unicorns


				

			

	*/});

```



Which outputs:



```



	

		
❤ unicorns


	



```



### String substitution



`console.log()` supports [string substitution](http://nodejs.org/docs/latest/api/console.html#console_console_log_data):



```js

const str = 'unicorns';



console.log(multiline(()=>{/*

  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

const str = multiline(/*



	

		
❤ unicorns


	



*/);

```



## FAQ



### But JS already has multiline strings with `\`?



```js

const 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

const str = 'foo\n\

bar';

```



But then you could just as well concatenate:



```js

const str = 'foo\n' +

'bar';

```



## Browser



While it does work fine in the browser, it's mainly intended for use in Node.js. Use at your own risk.



```

$ npm install multiline

```



With Webpack, Browserify, or something similar.



### 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

const str = multiline(function(){/*!@preserve



	

		
❤ unicorns


	



*/console.log});

```



## License



MIT © [Sindre Sorhus](https://sindresorhus.com)