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I want to display a bar chart - each bar is a user/student. And for each student, there will be an xAxis label displaying the students name
The below code is a VueJS computed property and called chartData
My data array for the bar chart is an array of objects. Here is how i generate it
let dataRow = this.responses.map((d) => {
return {
label: d.user.name,
data: [d.grade],
}
});
Here is how I generate my labels
let users = [];
this.responses.map((d) => {
users.push(d.user.name)
});
I then return on object with an array of labels and datasets with data being an array of objects
return {
labels: users,
datasets: [{
data: dataRow
}],
}
Here is how I render the chart:
{
extends: Bar,
props: ["chartdata"],
data() {
return {
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
yAxes: [{
ticks: {
beginAtZero: true,
max: 100
}
}],
},
}
}
},
mounted() {
this.renderChart(this.chartdata, this.options)
}
}
Issue: Nothing displays and there are no errors
The bar chart only seems to work when the data in the datasets is not an array of object like:
testData: {
labels: ['test', 'test', 'test'],
datasets: [{
data: [65, 59, 80],
}]
}
After Sayf-Eddine comment, i have managed to achieve this:
I changed how i returned the chartdata like:
return {
labels: users,
datasets: dataRow
}
However, all bars are mapping to the first label
After Vitaliy Rayets comment i figured out what was wrong
i needed to return the data row like:
let dataRow = this.responses.map((d) => {
return {
label: d.user.name,
y: [d.grade],
}
});
**I changed the property 'data' to 'y' **
I am doing a project where I need to be able to change the data array of a chart with a totally different one. My code is working for the labels of the chart, but the data is not changing, and I dont understand why. Hope you can help me, thanks in advance.
Here is my code :
var label = [];
var testArray= [{"production":"12","mois":"janvier"},{"production":"5","mois":"février"},{"production":"9","mois":"mars"},{"production":"17","mois":"avril"},{"production":"6","mois":"mai"},{"production":"8","mois":"juin"},{"production":"17","mois":"juillet"},{"production":"7","mois":"aout"},{"production":"10","mois":"septembre"}];
var chartData = {
labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
datasets: [{
label: '# of Votes',
data: [7, 4, 3, 5, 2, 3]
}]
};
var newdata = [];
function updateData(){
chartData.datasets.data = testArray.map(function (item) {
return item.production;
});
chartData.labels = testArray.map(function (item) {
return item.mois;
});
graphique.destroy();
graphInit();
}
function graphInit() {
graphique = new Chart(ctx, {
type: 'bar',
data: chartData,
options: {
scales: {
yAxes: [{
ticks: {
beginAtZero: true
}
}]
}
}
});
}
Inside function updateData, you need to access the data with chartData.datasets[0].data. Further you should update data with an array of number instead of string. Use Number to convert string to number as follows:
chartData.datasets[0].data = testArray.map(function (item) {
return Number(item.production);
});
this can also be written in a simpler way:
chartData.datasets[0].data = testArray.map(item => Number(item.production));
Also instead of graphique.destroy() and graphInit() you can simply use graphique.update(). Maybe this answer is of some further help too: https://stackoverflow.com/a/60091960/2358409.
I have been trying many ways to push the collection of array into the dataset.
Anyone can help me to push an array into stacked chart based on the codepen below?
Here's the example
Codepen stacked bar
Javascript
const getData = ()=>new Array(7).fill('').map(v=>randomScalingFactor());
var barChartData = {
labels: ['January', 'February', 'March', 'April', 'May', 'June', 'July'],
datasets: [{
label: 'Dataset 1',
backgroundColor: window.chartColors.red,
data: getData()
}, {
label: 'Dataset 2',
backgroundColor: window.chartColors.blue,
data: getData()
}, {
label: 'Dataset 3',
backgroundColor: window.chartColors.green,
data: getData()
}]
};
var ctx = document.getElementById('canvas').getContext('2d');
window.myBar = new Chart(ctx, {
type: 'bar',
data: barChartData,
options: {
title: {
display: true,
text: 'Chart.js Bar Chart - Stacked'
},
tooltips: {
mode: 'index',
intersect: false
},
responsive: true,
scales: {
xAxes: [{
stacked: true,
}],
yAxes: [{
stacked: true
}]
}
}
});
document.getElementById('randomizeData').addEventListener('click', function() {
barChartData.datasets.forEach(dataset=>{
dataset.data = getData();
});
window.myBar.update();
});
Here's the data for arrays
The issues should be the dataset with different colors and total should be the value for Y axis and there should be another collection of array date for X axis and the colors for the dataset should be different. The data for issues and total will be retrieved from Mysql database.
I am using laravel and the table above was achieved using foreach loop.
You really should provide more information. What have you tried, what failed...
Don't expect people do your job, wasting their time so you can nap for an hour. StackOverflow is for specific questions and not for letting others do somebody else's work. And getting data for chart.js is something trivial you can find in any other post about chart.js.
Enough ranting, just letting you know you shouldn't expect answers in the future for questions like that.
The code you posted in your question is quite different to the one from the codepen link, but this can be due to Narendra Jadhav's 'update'. But if confused me enough so I don't know what you want.
You didn't stated if you want to update our data so I didn't implemented updating.
Don't know the use case of this random randomizeData() does, especially with the fixed length of 7. I changed it but as I don't know the reason it may be different to your use case.
I don't know the data format you get from MySQL so I used a possible format. Same as above, could be different to what you want.
Please use an newer version of chart.js and not a year old version. There are no breaking changes, only improvements. Just updating the version eliminated a few bugs, e.g. the strange space between the yAxis and the chart.
Complete code (same as JSBin):
var initialData = [
{
'Barcode Sticker Problem':1,
'Extra':1,
'Labelling Problem':2,
'Stock Accuracy':1,
'Wrong Quality':1
},{
'Barcode Sticker Problem':1,
'Extra':1,
'Labelling Problem':2,
'Stock Accuracy':1,
'Wrong Quality':3
},
{
'Barcode Sticker Problem':2,
'Extra':2,
'Labelling Problem':1,
'Stock Accuracy':2,
'Wrong Quality':3
}
]
const colors = [
'red',
'blue',
'green'
]
var barChartData = {
labels: Object.keys(initialData[0]),
datasets: []
};
for (var i = 0; i < initialData.length; i++) {
barChartData.datasets.push(
{
label: 'Dataset ' + (i+1),
backgroundColor: colors[i % colors.length],
data: Object.values(initialData[i])
}
)
}
var barChartOptions = {
title: {
display: false,
text: 'Chart.js Stacked Bar Chart'
},
tooltips: {
mode: 'index',
intersect: false
},
responsive: true,
scales: {
xAxes: [{
stacked: true,
}],
yAxes: [{
stacked: true,
ticks: {
precision: 0
}
}]
}
}
var ctx = document.getElementById('canvas').getContext('2d');
window.myBar = new Chart(ctx, {
type: 'bar',
data: barChartData,
options: barChartOptions
});
document.getElementById('randomizeData').addEventListener('click', function() {
barChartData.datasets.forEach(dataset=>{
var newData = []
for (var i = 0; i < dataset.data.length; i++) {
newData.push(Math.floor(Math.random()*3)+1)
}
dataset.data = newData
});
window.myBar.update();
});
I have the following array:
Where the arrays keys are the dates and the only element I want to plot, of each set, is the weight. Look:
I am putting the code as follows. Notice that I am already grouping in the date attribute the whole set belonging to each that key.
var ctx = document.getElementById("barChart").getContext("2d");
var data = {
labels: ['21/03/2018','01/04/2018','02/04/2018','04/04/2018','05/04/2018','06/04/2018'],
datasets: [
{
label: '21/03/2018',
data: [12, 0, 0]
},
{
label: '01/04/2018',
data: [15.00, 15.00,15.00]
},
{
label: '02/04/2018',
data: [25.00, 25.00, 25.00]
},
{
label: '04/04/2018',
data: [25.00, 25.00, 25.00]
},
{
label: '05/04/2018',
data: [-8.14,-7.93, -7.84]
},
{
label: '06/04/2018',
data: [-35.9 ,-38.1, -37.5]
},
]
};
var myBarChart = new Chart(ctx, {
type: 'bar',
data: data,
});
But in this way ChartJs does not understand that it only needs to plot the data set present in the "data" attribute and grouping them by the key. Plotting the graph in the wrong way.
How could I plot the data correctly knowing that they are already grouped?
You need to organize your data as such:
var ctx = document.getElementById("canvas").getContext("2d");
var data = {
labels: ['21/03/2018','01/04/2018','02/04/2018','04/04/2018','05/04/2018','06/04/2018'],
datasets: [
{
data: [12, 15.00, 25.00, 25.00, -8.14, -35.9]
},{
data: [0, 15.00, 25.00, 25.00, -7.93, -38.1]
},{
data: [0, 15.00, 25.00, 25.00, -7.84, -37.5]
}
]
};
var myBarChart = new Chart(ctx, {
type: 'bar',
data: data,
options:{
legend: 'none'
}
});
I took your legend out as it's useless in this case. To look at it in the coding persepective, whatever index the date in labels is at needs to correlate with the index of the information you want to display in that grouping. data[0] refers to labels[0] and so on.
I've just started working with Chart.js, and I am getting very frustrated very quickly. I have my stacked bar chart working, but I can't get the click "events" to work.
I have found a comment on GitHub by nnnick from Chart.js stating to use the function getBarsAtEvent, even though this function cannot be found in the Chart.js documentation at all (go ahead, do a search for it). The documentation does mention the getElementsAtEvent function of the chart reference, but that is for Line Charts only.
I set an event listener (the right way) on my canvas element:
canv.addEventListener('click', handleClick, false);
...yet in my handleClick function, chart.getBarsAtEvent is undefined!
Now, in the Chart.js document, there is a statement about a different way to register the click event for the bar chart. It is much different than nnnick's comment on GitHub from 2 years ago.
In the Global Chart Defaults you can set an onClick function for your chart. I added an onClick function to my chart configuration, and it did nothing...
So, how the heck do I get the on-click-callback to work for my bar chart?!
Any help would be greatly appreciated. Thanks!
P.S.: I am not using the master build from GitHub. I tried, but it kept screaming that require is undefined and I was not ready to include CommonJS just so that I could use this chart library. I would rather write my own dang charts. Instead, I downloaded and am using the Standard Build version that I downloaded straight from the link at the top of the documentation page.
EXAMPLE: Here is an example of the configuration I am using:
var chart_config = {
type: 'bar',
data: {
labels: ['One', 'Two', 'Three'],
datasets: [
{
label: 'Dataset 1',
backgroundColor: '#848484',
data: [4, 2, 6]
},
{
label: 'Dataset 2',
backgroundColor: '#848484',
data: [1, 6, 3]
},
{
label: 'Dataset 3',
backgroundColor: '#848484',
data: [7, 5, 2]
}
]
},
options: {
title: {
display: false,
text: 'Stacked Bars'
},
tooltips: {
mode: 'label'
},
responsive: true,
maintainAspectRatio: false,
scales: {
xAxes: [
{
stacked: true
}
],
yAxes: [
{
stacked: true
}
]
},
onClick: handleClick
}
};
I managed to find the answer to my question by looking through the Chart.js source code.
Provided at line 3727 of Chart.js, Standard Build, is the method .getElementAtEvent. This method returns me the "chart element" that was clicked on. There is sufficent data here to determine what data to show in a drill-down view of the dataset clicked on.
On the first index of the array returned by chart.getElementAtEvent is a value _datasetIndex. This value shows the index of the dataset that was clicked on.
The specific bar that was clicked on, I believe, is noted by the value _index. In my example in my question, _index would point to One in chart_config.data.labels.
My handleClick function now looks like this:
function handleClick(evt)
{
var activeElement = chart.getElementAtEvent(evt);
..where chart is the reference of the chart created by chart.js when doing:
chart = new Chart(canv, chart_config);
The specific set of data that was selected by the click can therefore be found as:
chart_config.data.datasets[activeElement[0]._datasetIndex].data[activeElement[0]._index];
And there you have it. I now have a datapoint that I can build a query from to display the data of the bar that was clicked on.
AUGUST 7TH, 2021. UPDATE
There is now a method for what we are looking for. Take a look at here
Hi this is the click event under options which is getting values from x and y-axis
onClick: function(c,i) {
e = i[0];
console.log(e._index)
var x_value = this.data.labels[e._index];
var y_value = this.data.datasets[0].data[e._index];
console.log(x_value);
console.log(y_value);
}
I found this solution at https://github.com/valor-software/ng2-charts/issues/489
public chartClicked(e: any): void {
if (e.active.length > 0) {
const chart = e.active[0]._chart;
const activePoints = chart.getElementAtEvent(e.event);
if ( activePoints.length > 0) {
// get the internal index of slice in pie chart
const clickedElementIndex = activePoints[0]._index;
const label = chart.data.labels[clickedElementIndex];
// get value by index
const value = chart.data.datasets[0].data[clickedElementIndex];
console.log(clickedElementIndex, label, value)
}
}
}
You can use onClick like this.
var worstCells3GBoxChart = new Chart(ctx, {
type: 'bar',
data: {
labels: lbls,
datasets: [{
label: 'Worst Cells by 3G',
data: datas,
backgroundColor: getColorsUptoArray('bg', datas.length),
borderColor: getColorsUptoArray('br', datas.length),
borderWidth: 1
}]
},
options: {
legend: {
display: false
},
scales: {
yAxes: [{
ticks: {
beginAtZero: true
}
}]
},
onClick: function (e) {
debugger;
var activePointLabel = this.getElementsAtEvent(e)[0]._model.label;
alert(activePointLabel);
}
}
});
Chartjs V3.4.1
This is what worked for me in v3, after looking at solutions for older versions:
const onClick = (event, clickedElements) => {
if (clickedElements.length === 0) return
const { dataIndex, raw } = clickedElements[0].element.$context
const barLabel = event.chart.data.labels[dataIndex]
...
}
raw is the value of the clicked bar.
barLabel is the label of the clicked bar.
You need to pass the onClick to the bar chart config:
const barConfig = {
...
options: {
responsive: true,
onClick,
...
}
}
Well done! This seems to return the data value being charted though, which in many cases might be possible to appear more than once, thus making it unclear what was clicked on.
This will return the actual data label of the bar being clicked on. I found this more useful when drilling down into a category.
chart_config.data.labels[activeElement[0]._index]
I was able to make this work in another way.
Might not be supported, but sometimes, I find that neither the label nor the value is adequate to get me the necessary information to populate a drill-through.
So what I did was add a custom set of attributes to the data:
var ctx = document.getElementById("cnvMyChart").getContext("2d");
if(theChart != null) {theChart.destroy();}
theChart = new Chart(ctx, {
type: typ,
data: {
labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
datakeys: ["thefirstone","thesecondone","thethirdone","thefourthone","thefifthone","thesixthone"],
datasets: [{
label: '# of Votes',
data: [12, 19, 3, 5, 2, 3],
...etc
Then when I need to push the drillthrough key into another ajax call, I was able to get it with this:
var theDrillThroughKey = theChart.config.data.datakeys[activePoints[0]._index];
So I'm really not sure that it's appropriate to be adding custom elements into the data for the Chart, but it's working so far in Chrome, IE and Firefox. I needed to be able to put more information into the drillthrough than I really wanted displayed.
Example of the full thing: https://wa.rrdsb.com/chartExamples
Thoughts?
I had the same problem with multiple datasets, and used this workaround:
var clickOnChart = function(dataIndex){
...
}
var lastHoveredIndex = null;
var chart_options = {
...
tooltips: {
...
callbacks: {
label: function(tooltipItem, chart) {
var index = tooltipItem.datasetIndex;
var value = chart.datasets[index].data[0];
var label = chart.datasets[index].label;
lastHoveredIndex = index;
return value + "€";
}
}
},
onClick:function(e, items){
if ( items.length == 0 ) return; //Clicked outside any bar.
clickOnChart(lastHoveredIndex);
}
}
Let's say that you declared a chart using a method like so:
window.myBar = new Chart({chart_name}, {
type: xxx,
data: xxx,
events: ["click"],
options: {
...
}
});
A good way of declaring onclick events would involve listening for the canvas click, like so:
({chart_name}.canvas).onclick = function(evt) {
var activePoints = myBar.getElementsAtEvent(evt);
// let's say you wanted to perform different actions based on label selected
if (activePoints[0]._model.label == "label you are looking for") { ... }
}
In the chart options for Chart.js v3.5.1 which is latest
Check below sample code
let enterpriseChartOptions = {
responsive:true,
maintainAspectRatio: false,
onClick: (c,i) => {
console.log('Get the underlying label for click,', c.chart.config._config.data.labels[i[0].index]);
},
plugins: {
title:{
text:'Enterprise Dashboard (Health Status of 10 stores) updated every 30 minutes',
fontSize:20
},
},
scales: {
x: {
display: true,
type: 'category',
position: 'right',
ticks: {
padding: 8,
},
},
y: {
display: true,
ticks: {
callback: function(val, index) {
// Show the label
return val < 1 ? "All good" : (val < 2 && val >=1) ? "Warning": val === 2 ? "Critical" : "";
},
//color: 'red',
stepSize: 1,
padding: 8
}
}
},
layout: {
padding: {
left: 20,
right: 20,
top: 25,
bottom: 0
}
},
};
var employeeDetailsCtx = document.getElementById("employee-details").getContext("2d");
var employee_details_data = {
labels: ["Late Present", "On Leave", "Training", "Tour"],
datasets: [{
label: "Officer",
backgroundColor: "#5A8DEE",
data: [
...
]
}, {
label: "Staff",
backgroundColor: "#4BC0C0",
data: [
...
]
}]
};
var myoption = {
tooltips: {
enabled: true
},
hover: {
animationDuration: 1
},
onClick: function (evt, i) {
var activePoint = employeeDetailsBarChart.getElementAtEvent(evt)[0];
var data = activePoint._chart.data;
var datasetIndex = activePoint._datasetIndex;
var label = data.datasets[datasetIndex].label;
var value = data.datasets[datasetIndex].data[activePoint._index];
e = i[0];
var x_value = this.data.labels[e._index];
console.log(x_value)
console.log(label)
console.log(value)
},
animation: {
duration: 1,
onComplete: function () {
var chartInstance = this.chart,
ctx = chartInstance.ctx;
ctx.textAlign = 'center';
ctx.fillStyle = "rgba(0, 0, 0, 1)";
ctx.textBaseline = 'bottom';
this.data.datasets.forEach(function (dataset, i) {
var meta = chartInstance.controller.getDatasetMeta(i);
meta.data.forEach(function (bar, index) {
var data = dataset.data[index];
ctx.fillText(data, bar._model.x, bar._model.y - 5);
});
});
}
}
};
var employeeDetailsBarChart = new Chart(employeeDetailsCtx, {
type: 'bar',
data: employee_details_data,
options: myoption
});