Handlebar helper I use with grunt-assemble to generate charts as images for a static blog

charts.js

	Handlebars.registerHelper('chart', function(width, height, type, title, options) {
		var config = JSON.parse(options.fn(this)),
			canvas = new Canvas(width, height),
			ctx = canvas.getContext('2d'),
			method = type[0].toUpperCase() + type.slice(1),
			uniqueName = crypto.createHash('md5').update(width + height + type + title + options.fn(this)).digest('hex'),
			chartFileName = uniqueName + '.png';

		new Chart(ctx)[method](config);

		canvas.toBuffer(function (err, buf) {
			if (err) throw err;
			fs.writeFileSync(path.join(__dirname, '..', 'build', 'charts', chartFileName), buf);
		});

		return new Handlebars.SafeString(
			'<figure class="chart fullwidth">' +
			'<img src="/charts/' + chartFileName + '" alt="' + title + '">' +
			'<figcaption>' + title + '</figcaption>' +
			'</figure>'
		);
	});