window.onload = function() {
var isFirstLevel = ko.observable(true),
dataSource = ko.observable(filterData("")),
buttonIsVisible = ko.computed(function () {
return !isFirstLevel();
});
var viewModel = {
chartOptions: {
dataSource: dataSource,
title: "The Most Populated Countries by Continents",
series: {
type: "bar"
},
legend: {
visible: false
},
valueAxis: {
showZero: false
},
onPointClick: function (e) {
if (isFirstLevel()) {
isFirstLevel(false);
removePointerCursor();
dataSource(filterData(e.target.originalArgument));
}
},
customizePoint: function () {
var pointSettings = {
color: colors[Number(isFirstLevel())]
};
if (!isFirstLevel()) {
pointSettings.hoverStyle = {
hatching: "none"
};
}
return pointSettings;
}
},
buttonOptions: {
text: "Back",
icon: "chevronleft",
visible: buttonIsVisible,
onClick: function () {
if (!isFirstLevel()) {
isFirstLevel(true);
addPointerCursor();
dataSource(filterData(""));
}
}
}
};
ko.applyBindings(viewModel, document.getElementById("chart-demo"));
addPointerCursor();
function filterData(name) {
return data.filter(function (item) {
return item.parentID === name;
});
}
function addPointerCursor() {
document.getElementById("chart").classList.add("pointer-on-bars");
}
function removePointerCursor() {
document.getElementById("chart").classList.remove("pointer-on-bars");
}
};
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>DevExtreme Demo</title>
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script>window.jQuery || document.write(decodeURIComponent('%3Cscript src="js/jquery.min.js"%3E%3C/script%3E'))</script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.4.2/knockout-min.js"></script>
<link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/19.2.4/css/dx.common.css" />
<link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/19.2.4/css/dx.light.css" />
<script src="https://cdn3.devexpress.com/jslib/19.2.4/js/dx.all.js"></script>
<script src="data.js"></script>
<link rel="stylesheet" type="text/css" href="styles.css" />
<script src="index.js"></script>
</head>
<body class="dx-viewport">
<div class="demo-container">
<div id="chart-demo">
<div id="chart" data-bind="dxChart: chartOptions"></div>
<div class="button-container">
<div id="backButton" data-bind="dxButton: buttonOptions"></div>
</div>
</div>
</div>
</body>
</html>
#chart {
height: 440px;
width: 100%;
}
#chart.pointer-on-bars .dxc-series rect {
cursor: pointer;
}
.button-container {
text-align: center;
height: 40px;
position: absolute;
top: 7px;
left: 0px;
}
var colors = ["#6babac", "#e55253"];
var data = [
{ arg: "Asia", val: 3007613498, parentID: "" },
{ arg: "North America", val: 493603615, parentID: "" },
{ arg: "Europe", val: 438575293, parentID: "" },
{ arg: "Africa", val: 381331438, parentID: "" },
{ arg: "South America", val: 331126555, parentID: "" },
{ arg: "Nigeria", val: 181562056, parentID: "Africa" },
{ arg: "Egypt", val: 88487396, parentID: "Africa" },
{ arg: "Congo", val: 77433744, parentID: "Africa" },
{ arg: "Morocco", val: 33848242, parentID: "Africa" },
{ arg: "China", val: 1380083000, parentID: "Asia" },
{ arg: "India", val: 1306687000, parentID: "Asia" },
{ arg: "Pakistan", val: 193885498, parentID: "Asia" },
{ arg: "Japan", val: 126958000, parentID: "Asia" },
{ arg: "Russia", val: 146804372, parentID: "Europe" },
{ arg: "Germany", val: 82175684, parentID: "Europe" },
{ arg: "Turkey", val: 79463663, parentID: "Europe" },
{ arg: "France", val: 66736000, parentID: "Europe" },
{ arg: "United Kingdom", val: 63395574, parentID: "Europe" },
{ arg: "United States", val: 325310275, parentID: "North America" },
{ arg: "Mexico", val: 121005815, parentID: "North America" },
{ arg: "Canada", val: 36048521, parentID: "North America" },
{ arg: "Cuba", val: 11239004, parentID: "North America" },
{ arg: "Brazil", val: 205737996, parentID: "South America" },
{ arg: "Colombia", val: 48400388, parentID: "South America" },
{ arg: "Venezuela", val: 30761000, parentID: "South America" },
{ arg: "Peru", val: 28220764, parentID: "South America" },
{ arg: "Chile", val: 18006407, parentID: "South America" }
];