Multiline strings in JavaScript
No more string concatenation or array join!
Note that ES6 will have template string which can be multiline, but time...
var str = '' +
'<!doctype html>' +
'<html>' +
' <body>' +
' <h1>❤ unicorns</h1>' +
' </body>' +
'</html>' +
'';
var str = multiline(function(){/*
<!doctype html>
<html>
<body>
<h1>❤ unicorns</h1>
</body>
</html>
*/});
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.
$ npm install --save multiline
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>
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>
A real-world use case from my pageres module.
Another use case is for query strings. Here's an example in Cypher, the query language for Neo4j.
Have one? Let me know.
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>
*/);
\?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.
While it does work fine in the browser, it's mainly intended for use in Node.js.
Download manually or with a package-manager.
$ bower install --save multiline
$ component install sindresorhus/multiline
Even though minifiers strip comments by default there are ways to preserve them:
/*@preserve instead of /* and enable the comments option/*@preserve instead of /*/*! instead of /*You also need to add 0 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>
*/0});
FAQs
Multiline strings in JavaScript
The npm package multiline receives a total of 88,540 weekly downloads. As such, multiline popularity was classified as popular.
We found that multiline demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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