multiline-supplant
v0.1.0
Published
Multiline strings in JavaScript (with Doug Crockford's String supplant)
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ekmartinReadme
multiline 
Multiline strings in JavaScript
No more string concatenation or array join!
Note that ES6 will have template string which can be multiline, but time...
Before
var str = '' +
'<!doctype html>' +
'<html>' +
' <body>' +
' <h1>❤ unicorns</h1>' +
' </body>' +
'</html>' +
'';After
var str = multiline(function(){/*
<!doctype html>
<html>
<body>
<h1>❤ unicorns</h1>
</body>
</html>
*/});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, that shouldn't realistically matter as you can still do 2 million of those a second. Convenience over micro performance always.
Install
$ npm install --save multilineUsage
Everything after the first newline and before the last will be returned as seen below:
var str = multiline(function(){/*
<!doctype html>
<html>
<body>
<h1>❤ unicorns</h1>
</body>
</html>
*/});Which outputs:
<!doctype html>
<html>
<body>
<h1>❤ unicorns</h1>
</body>
</html>Strip indent
You can use multiline.stripIndent() to be able to indent your multiline string without preserving the redundant leading whitespace.
var str = multiline.stripIndent(function(){/*
<!doctype html>
<html>
<body>
<h1>❤ unicorns</h1>
</body>
</html>
*/});Which outputs:
<!doctype html>
<html>
<body>
<h1>❤ unicorns</h1>
</body>
</html>String substitution
console.log() supports string substitution:
var str = 'unicorns';
console.log(multiline(function(){/*
I love %s
*/}), str);
//=> I love unicornsUse cases
- CLI help output
- Test fixtures
- Queries - here an example in Cypher, the query language for Neo4j
- CLI welcome message - here in a Yeoman generator
Have one? Let me know.
Experiment
I've also done an experiment 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.
var str = multiline(/*
<!doctype html>
<html>
<body>
<h1>❤ unicorns</h1>
</body>
</html>
*/);FAQ
But JS already has multiline strings with \?
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:
var str = 'foo\n\
bar';But then you could just as well concatenate:
var str = 'foo\n' +
'bar';Note that ES6 will have real multiline 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
$ bower install --save multiline$ component install sindresorhus/multilineCompatibility
- 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
/*@preserveinstead of/*and enable thecommentsoption - Closure Compiler: Use
/*@preserveinstead 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:
var str = multiline(function(){/*!@preserve
<!doctype html>
<html>
<body>
<h1>❤ unicorns</h1>
</body>
</html>
*/console.log});License
MIT © Sindre Sorhus