An example of some js compiled from coffeescript. See https://gist.github.com/josh/2553381 The sourceMappingURL is an entire source map that includes the coffeescript source, encoded in a base64 data uri. This could be generated programmatically. Evalling a string containing this gists contents in chrome canary puts you into the debugger showing…

gistfile1.js

// Generated by CoffeeScript 1.3.1
(function() {
  var cubes, list, math, num, number, opposite, race, square,
			__slice = [].slice;

	number = 42;

	opposite = true;

	if (opposite) {
		number = -42;
	}

	square = function(x) {
		return x * x;
	};

	list = [1, 2, 3, 4, 5];

	math = {
		root: Math.sqrt,
		square: square,
		cube: function(x) {
			return x * square(x);
		}
	};

	race = function() {
		var runners, winner;
		winner = arguments[0], runners = 2 <= arguments.length ? __slice.call(arguments, 1) : [];
		return print(winner, runners);
	};

	if (typeof elvis !== "undefined" && elvis !== null) {
		alert("I knew it!");
	}
debugger;
	cubes = (function() {
		var _i, _len, _results;
		_results = [];
		for (_i = 0, _len = list.length; _i < _len; _i++) {
			num = list[_i];
			_results.push(math.cube(num));
		}
		return _results;
	})();

}).call(this);
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