jasmine diff matcher

jasmine.addMatchers( jasmine.XXX.customMatchers );

// This must load before any tests are run.
jasmine.XXX.customMatchers = {
	toEqualNice: function(util, customEqualityTesters) {
		return {
			compare: function(actual, expected) {
				if (expected === undefined) {
					expected = '';
				}
				var result = {};
				result.pass = util.equals(actual, expected, customEqualityTesters);
				if (! result.pass) {
					result.message = 'Expected:\n\t'+ JSON.stringify(expected, null, '\t') + '\nReceived:\n\t' + JSON.stringify(actual, null, '\t');
					result.message += '\nDiff:\n\n';
					var diff = JsDiff.diffLines( 
						JSON.stringify(expected, null, '  '),
						JSON.stringify(actual, null, '  ')
					);

					diff.forEach(function(part){
						var marker = part.added ? '+++ ' :
							part.removed ? '--- ' : '    ';
					  		result.message += marker + part.value + '\n'
					});

				}
				return result;
			}
		};
	}
};