window.onload = function () {
const isFirstLevel = ko.observable(true);
const dataSource = ko.observable(filterData(''));
const buttonIsVisible = ko.computed(() => !isFirstLevel());
const viewModel = {
chartOptions: {
dataSource,
title: 'The Most Populated Countries by Continents',
series: {
type: 'bar',
},
legend: {
visible: false,
},
valueAxis: {
showZero: false,
},
onPointClick(e) {
if (isFirstLevel()) {
isFirstLevel(false);
removePointerCursor();
dataSource(filterData(e.target.originalArgument));
}
},
customizePoint() {
const pointSettings = {
color: colors[Number(isFirstLevel())],
};
if (!isFirstLevel()) {
pointSettings.hoverStyle = {
hatching: 'none',
};
}
return pointSettings;
},
},
buttonOptions: {
text: 'Back',
icon: 'chevronleft',
visible: buttonIsVisible,
onClick() {
if (!isFirstLevel()) {
isFirstLevel(true);
addPointerCursor();
dataSource(filterData(''));
}
},
},
};
ko.applyBindings(viewModel, document.getElementById('chart-demo'));
addPointerCursor();
function filterData(name) {
return data.filter((item) => 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/3.5.1/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/22.2.3/css/dx.light.css" />
<script src="https://cdn3.devexpress.com/jslib/22.2.3/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: 0;
}
const colors = ['#6babac', '#e55253'];
const 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' },
];