Javascript HEREDOC (and simple method for injecting CSS as style block)

the.js

/** Created by stephen on 3/12/15. */
'use strict';

/**
 * Convenience function for hardocding multiline strings, without needing use explicit "\n" and concatenate lines.
 * @param {function} fn - A function with a block comment as it's entire definition. Will not be executed.
 * @return {string} The contents of the block comment in the definition of @param fn. 
 */
function HEREDOC( fn ){
	return fn.toString().match( /\/\*[\n\l]?([\s\S]*?)\*\//m )[1];
};

///////////////
// EXAMPLE 1 //
///////////////

console.log( HEREDOC( function(){/*
This
is
a 
test
*/}));

///////////////
// EXAMPLE 2 //
///////////////

/**
 * Add css into the current document.
 * @param {string} css - The CSS to parse. Can includ line comments (non-CSS) by beginning line with "//".
 * @param {boolean} removeLineComments - Optional. If true, will remove lines starting with "//".  Otherwise, will convert to CSS-style block comments.
 */
function injectCss( css, removeLineComments ){
  var el = document.createElement('style');
  el.innerHTML = css.replace(/[\s\n]\/\/\s?(.*)$/mg, removeLineComments ? '' : '/* $1 */' );
  document.head.appendChild( el );
}
injectCss( HEREDOC( function(){/*
// Outline everything!
* { border: 1px solid green; }
// Fade everything!
html { opacity: 0.5; }
*/}));