Chart.js Knockout bindings

ko-chart.js

/*global ko, Chart */

(function(ko, Chart) {

	ko.bindingHandlers.chartType = {
		init: function(element, valueAccessor, allBindings, viewModel, bindingContext) {
			if (!allBindings.has('chartData')) {
				throw Error('chartType must be used in conjunction with chartData and (optionally) chartOptions');
			}
		},
		update: function (element, valueAccessor, allBindings, viewModel, bindingContext) {
			var ctx = element.getContext('2d'),
				type = ko.unwrap(valueAccessor()),
				data = ko.unwrap(allBindings.get('chartData')),
				options = ko.unwrap(allBindings.get('chartOptions')) || {};
			
			ko.utils.domNodeDisposal.addDisposeCallback(element, function() {
                        	$(element).chart.destroy();
                		delete $(element).chart;
                    	});

                    	$(element).chart = new Chart(ctx)[type](data, options);
		}
	};

	ko.bindingHandlers.chartData = {
		init: function(element, valueAccessor, allBindings, viewModel, bindingContext) {
			if (!allBindings.has('chartType')) {
				throw Error('chartData must be used in conjunction with chartType and (optionally) chartOptions');
			}
		}
	};

	ko.bindingHandlers.chartOptions = {
		init: function(element, valueAccessor, allBindings, viewModel, bindingContext) {
			if (!allBindings.has('chartData') || !allBindings.has('chartType')) {
				throw Error('chartOptions must be used in conjunction with chartType and chartData');
			}
		}
	};

})(ko, Chart);