Develop Reference

One common component for Chart.js to use with different y-axis With React.js

useEffect(() => {
let ctx = document.getElementById("LineChart");
const blue = [2000, 2100, 2400, 2450, 3000];
const yellow = [1800, 2150, 2550, 2800, 2000];
const pink = [1200, 1100, 1050, 1010, 1000];
const LineChart = new Chart(ctx, {
type: "line",
data: {
labels: ["Jan", "Feb", "Mar", "Apr", "May"],
datasets: [
{
data: blue,
label: "New MRR",
fill: false,
lineTension: 0.5,
backgroundColor: "#3ea5e0",
borderColor: "#3ea5e0",
pointBorderWidth: 1,
pointHoverBackgroundColor: "rgba(75,192,192,1)",
pointRadius: 1,
pointHitRadius: 10,
},
{
data: yellow,
label: "Net New MRR",
fill: false,
lineTension: 0.5,
backgroundColor: "#ad9a52",
borderColor: "#ad9a52",
pointBorderWidth: 1,
pointHoverBackgroundColor: "rgba(75,192,192,1)",
pointRadius: 1,
pointHitRadius: 10,
},
{
data: pink,
label: "Lost MRR",
fill: false,
lineTension: 0.5,
backgroundColor: "#5c3784",
borderColor: "#5c3784",
pointBorderWidth: 1,
pointHoverBackgroundColor: "rgba(75,192,192,1)",
pointRadius: 1,
pointHitRadius: 10,
},
],
},
options: {
scales: {
yAxes: [
{
ticks: {
beginAtZero: false,
callback: function (value, index, values) {
return "$" + value;
},
},
},
],
},
},
});
let ctx2 = document.getElementById("BarChart");
const BarChart = new Chart(ctx2, {
type: "bar",
data: data,
});
I want to create a common chart component with same x-axis values but different y-axis values.I have switch case according to their type.So I can render charts with their types.Is there a short way to create a common chart or do I have to code all of them? Because right now I can only render one line chart.

Here is how you can create a common Chart component which will draw the chart given a custom data.
https://codesandbox.io/s/serverless-frog-6bu2f?file=/src/App.js

Remove data after adding it (chart.js)

I have an add data function in my bar-chart but I would like to be able to remove this data with onclick. How do I do this?
var canvas = document.getElementById("barChart");
var ctx = canvas.getContext('2d');
// We are only changing the chart type, so let's make that a global variable along with the chart object:
var chartType = 'bar';
var myBarChart;
// Global Options:
Chart.defaults.global.defaultFontColor = 'grey';
Chart.defaults.global.defaultFontSize = 16;
var data = {
labels: [ "2012", "2013", "2014", "2015", "2016", "2017"],
datasets: [{
label: "Miljoner ton",
fill: true,
lineTension: 0.1,
backgroundColor: "rgba(0,255,0,0.4)",
borderColor: "green", // The main line color
borderCapStyle: 'square',
pointBorderColor: "white",
pointBackgroundColor: "green",
pointBorderWidth: 1,
pointHoverRadius: 8,
pointHoverBackgroundColor: "yellow",
pointHoverBorderColor: "green",
pointHoverBorderWidth: 2,
pointRadius: 4,
pointHitRadius: 10,
data: [56.38, 59.3, 61.81, 58.83, 52.32, 66.86],
spanGaps: true,
}]
};
// Notice the scaleLabel at the same level as Ticks
var options = {
scales: {
yAxes: [{
ticks: {
beginAtZero: true
}
}]
},
title: {
fontSize: 18,
display: true,
text: 'Källa: Globallife.org',
position: 'bottom'
}
};
function addData() {
myBarChart.data.labels[7] ="Ekologisk palmolja";
myBarChart.data.datasets[0].data[7] = 14;
myBarChart.update();
}
// We add an init function down here after the chart options are declared.
init();
function init() {
// Chart declaration:
myBarChart = new Chart(ctx, {
type: chartType,
data: data,
options: options
});
}

Below is a working example that demonstrates modifying and updating the chart when clicking a button. Your addData function is a little odd in that it adds data at index 7, but the dataset only has keys 0-5, so this causes an extra blank data point to be inserted at index 6.
In case this isn't what you intended, I added some extra functions (pushData and popData) to show adding and removing from the end of a dataset as that's a quite common requirement (and therefore documented).
// same as original function; inserts or updates index 7.
function addData(e) {
myBarChart.data.labels[7] = "Ekologisk palmolja";
myBarChart.data.datasets[0].data[7] = 14;
myBarChart.update();
}
// requested function; removes index 7.
function removeData(e) {
myBarChart.data.labels.splice(7, 1);
myBarChart.data.datasets[0].data.splice(7, 1);
myBarChart.update();
}
// example of how to add data point to end of dataset.
function pushData(e) {
myBarChart.data.labels.push("Ekologisk palmolja");
myBarChart.data.datasets[0].data.push(14);
myBarChart.update();
}
// example of how to remove data point from end of dataset.
function popData(e) {
myBarChart.data.labels.pop();
myBarChart.data.datasets[0].data.pop();
myBarChart.update();
}
// set listeners on buttons
document.getElementById('add1').addEventListener('click', addData);
document.getElementById('remove1').addEventListener('click', removeData);
document.getElementById('add2').addEventListener('click', pushData);
document.getElementById('remove2').addEventListener('click', popData);
Chart.defaults.global.defaultFontColor = 'grey';
Chart.defaults.global.defaultFontSize = 16;
let myBarChart = new Chart(document.getElementById('chart'), {
type: 'bar',
data: {
labels: ["2012", "2013", "2014", "2015", "2016", "2017"],
datasets: [{
label: "Miljoner ton",
fill: true,
lineTension: 0.1,
backgroundColor: "rgba(0,255,0,0.4)",
borderColor: "green", // The main line color
borderCapStyle: 'square',
pointBorderColor: "white",
pointBackgroundColor: "green",
pointBorderWidth: 1,
pointHoverRadius: 8,
pointHoverBackgroundColor: "yellow",
pointHoverBorderColor: "green",
pointHoverBorderWidth: 2,
pointRadius: 4,
pointHitRadius: 10,
data: [56.38, 59.3, 61.81, 58.83, 52.32, 66.86],
spanGaps: true
}]
},
options: {
maintainAspectRatio: false,
scales: {
yAxes: [{
ticks: {
beginAtZero: true
}
}]
},
title: {
fontSize: 18,
display: true,
text: 'Källa: Globallife.org',
position: 'bottom'
}
}
});
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.2/Chart.min.js"></script>
<canvas id="chart"></canvas>
<button id="add1">Add index 7</button>
<button id="remove1">Remove index 7</button>
<button id="add2">Add to end</button>
<button id="remove2">Remove from end</button>

Adding Chart.js line chart to Jinja2/Flask html page from JS file

I have the following code in a simple Bootstrap html file which displays a Chart.js line chart.
<div class="card-block chartjs">
<canvas id="line-chart" height="500"></canvas>
</div>
The js file that contains the chart's setup looks like this:
$(window).on("load", function(){
var ctx = $("#line-chart");
var chartOptions = {
responsive: true,
maintainAspectRatio: false,
legend: {
position: 'bottom',
},
hover: {
mode: 'label'
},
scales: {
xAxes: [{
display: true,
gridLines: {
color: "#f3f3f3",
drawTicks: false,
},
scaleLabel: {
display: true,
labelString: 'Month'
}
}],
yAxes: [{
display: true,
gridLines: {
color: "#f3f3f3",
drawTicks: false,
},
scaleLabel: {
display: true,
labelString: 'Value'
}
}]
},
title: {
display: true,
text: 'Chart.js Line Chart - Legend'
}
};
var chartData = {
labels: ["January", "February", "March", "April", "May", "June", "July"],
datasets: [{
label: "My First dataset",
data: [65, 59, 80, 81, 56, 55, 40],
fill: false,
borderDash: [5, 5],
borderColor: "#9C27B0",
pointBorderColor: "#9C27B0",
pointBackgroundColor: "#FFF",
pointBorderWidth: 2,
pointHoverBorderWidth: 2,
pointRadius: 4,
}, {
label: "My Second dataset",
data: [28, 48, 40, 19, 86, 27, 90],
fill: false,
borderDash: [5, 5],
borderColor: "#00A5A8",
pointBorderColor: "#00A5A8",
pointBackgroundColor: "#FFF",
pointBorderWidth: 2,
pointHoverBorderWidth: 2,
pointRadius: 4,
}, {
label: "My Third dataset - No bezier",
data: [45, 25, 16, 36, 67, 18, 76],
lineTension: 0,
fill: false,
borderColor: "#FF7D4D",
pointBorderColor: "#FF7D4D",
pointBackgroundColor: "#FFF",
pointBorderWidth: 2,
pointHoverBorderWidth: 2,
pointRadius: 4,
}]
};
var config = {
type: 'line',
options : chartOptions,
data : chartData
};
var lineChart = new Chart(ctx, config);
});
I would like to avoid using a separated javascript file and rather just have everything in my Jinja2/Flask html page. A working example can be found in this tutorial, this is the same way that I would like to follow. I have tried to copy any paste the js part to my html page and put between <script> tags, but unfortunately it doesn't work.
Here is how I tried:
# in my jinja2/flask html page
<div class="card-body collapse in">
<div class="card-block chartjs">
<canvas id="line-chart" height="500"></canvas>
</div>
</div>
<script>
var ctx = $("#line-chart");
var chartOptions = {
responsive: true,
maintainAspectRatio: false,
legend: {
position: 'bottom',
},
hover: {
mode: 'label'
},
scales: {
xAxes: [{
display: true,
gridLines: {
color: "#f3f3f3",
drawTicks: false,
},
scaleLabel: {
display: true,
labelString: 'Month'
}
}],
yAxes: [{
display: true,
gridLines: {
color: "#f3f3f3",
drawTicks: false,
},
scaleLabel: {
display: true,
labelString: 'Value'
}
}]
},
title: {
display: true,
text: 'Chart.js Line Chart - Legend'
}
};
// Chart Data
var chartData = {
labels: ["January", "February", "March", "April", "May", "June", "July"],
datasets: [{
label: "My First dataset",
data: [65, 59, 80, 81, 56, 55, 40],
fill: false,
borderDash: [5, 5],
borderColor: "#9C27B0",
pointBorderColor: "#9C27B0",
pointBackgroundColor: "#FFF",
pointBorderWidth: 2,
pointHoverBorderWidth: 2,
pointRadius: 4,
}, {
label: "My Second dataset",
data: [28, 48, 40, 19, 86, 27, 90],
fill: false,
borderDash: [5, 5],
borderColor: "#00A5A8",
pointBorderColor: "#00A5A8",
pointBackgroundColor: "#FFF",
pointBorderWidth: 2,
pointHoverBorderWidth: 2,
pointRadius: 4,
}, {
label: "My Third dataset - No bezier",
data: [45, 25, 16, 36, 67, 18, 76],
lineTension: 0,
fill: false,
borderColor: "#FF7D4D",
pointBorderColor: "#FF7D4D",
pointBackgroundColor: "#FFF",
pointBorderWidth: 2,
pointHoverBorderWidth: 2,
pointRadius: 4,
}]
};
var config = {
type: 'line',
// Chart Options
options : chartOptions,
data : chartData
};
// Create the chart
var lineChart = new Chart(ctx, config);
});
</script>
Unfortunately I'm not so familiar with JS and don't have more ideas about what should I do to display the chart in my Flask app. What do I need to implement to make it work?

First make sure the required JS is referenced in your template (or the template it extends).
Assuming you serve it from static/js folder:
<head>
...
<script src='/static/js/Chart.bundle.min.js'></script>
...
</head>
Your script tag content looks mostly fine, just a little modification getting the context, and you appear to have a trailing }); that you need to remove:
<script>
// get context
var ctx = document.getElementById("line-chart").getContext("2d");
....
// Create the chart
var lineChart = new Chart(ctx, config);
// REMOVE THIS FROM THE END OF YOUR SCRIPT
//});
</script>

As bgse said in his answer you need to load library first. I suggest you use CDN as that way you don't need to download ChartJS library.
Secondly, you're writing some JS that may be executed before library is fetched to the page. So what would I add is:
<div class="card-body collapse in">
<div class="card-block chartjs">
<canvas id="line-chart" height="500"></canvas>
</div>
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.6.0/Chart.min.js"></script>
<script src="https://code.jquery.com/jquery-3.2.1.min.js" integrity="sha256-hwg4gsxgFZhOsEEamdOYGBf13FyQuiTwlAQgxVSNgt4=" crossorigin="anonymous"></script>
<script>
$(document).ready(function(){
// Your JS code here
// ...
});
</script>
This way script code will execute when all JS is loaded.

How to fix the distance between horizontal points (x-axis) in chartJS

Problem: Hi all! i am using chart.js to draw the charts. chart is a dynamic sometimes shows 10 points and sometimes can be more than thousand i have applied a panel successfully so that my points can be shown at some distance to read them easily.
Right now i want to know if there is any option to set the distance between points in x-axis grid. right now it automatically adjust the points.
What i tried:
i tried to do the stepsize and scalewidth by searching other stackoverflow answers but did not succeed. Any kind of help would be much appreciated.
P.S: i m using chart.js2
This is my chartjs dataset
var data = {
labels: data.graph_date,
datasets: [
{
label: 'Assay Values',
fill: false,
lineTension: 0,
backgroundColor: "rgba(255, 0, 0,1)",
borderColor: "rgba(255, 0, 0,1)",
borderCapStyle: 'butt',
borderDash: [],
borderDashOffset: 0.0,
borderWidth: 1,
borderJoinStyle: 'miter',
pointBorderColor: "rgba(255, 0, 0,1)",
pointBackgroundColor: "#fff",
pointBorderWidth: 1,
pointHoverRadius: 5,
pointHoverBackgroundColor: "rgba(255, 0, 0,1)",
pointHoverBorderColor: "rgba(255, 0, 0,1)",
pointHoverBorderWidth: 2,
pointRadius: 1,
pointHitRadius: 10,
data: data.assay_value,
spanGaps: false
},var options = {
responsive: false,
title: {
display: true,
position: "top",
text: label,
fontSize: 18,
fontColor: "#111"
},
legend: {
display: true,
position: "bottom",
labels: {
fontColor: "#333",
fontSize: 16
}
},
tooltips: {
enabled: true,
mode: 'single',
callbacks: {
label: function(tooltipItems, data) {
var multistringText = ['Assay Value: '+tooltipItems.yLabel];
multistringText.push('Assigned Value: '+assigned_value[tooltipItems.index]);
multistringText.push('Sample ID: '+sample_id[tooltipItems.index]);
return multistringText;
}
}
},
scales:{
yAxes:[{
ticks:{
min:graph_min
}
}],
xAxes: [{
gridLines: {
display:false
}
}]
}
};
if(new_chart[ctx.canvas.id] != null)
new_chart[ctx.canvas.id].destroy();
new_chart[ctx.canvas.id] =new Chart(ctx, {
type: 'line',
data: data,
options: options
});
In x-axis there is data like this
[19-Aug-2015,21-Aug-2015,21-Aug-2015,21-Aug-2015,21-Aug-2015,22-Aug-2015,27-Aug-2015,29-Aug-2015,1-Sep-2015,2-Sep-2015,3-Sep-2015,]
in y-axis data is like this
[0.1,0.05,0.89,0.89,0.79,0.58,0.68,0.25,0.98]

The way to control distance between points it to set the X and Y axis with a min, max, and step size so that they never change regardless of the number of points that are in the chart.
Here is an example that sets the scales so that they will never change. Regardless of how many points appear on the chart everything will stay the same.
var ctx = document.getElementById("myChart");
var myChart = new Chart(ctx, {
type: 'line',
data: {
datasets: [{
label: 'Points',
data: [
{x: 0, y: 2},
{x: 1, y: 3},
{x: 2, y: 2},
{x: 1.02, y: 0.4},
{x: 0, y: -1}
],
backgroundColor: 'rgba(123, 83, 252, 0.8)',
borderColor: 'rgba(33, 232, 234, 1)',
borderWidth: 1,
fill: false,
showLine: false,
}],
},
options: {
title: {
display: true,
text: 'Chart.js - Fixed X and Y Axis',
},
scales: {
xAxes: [{
type: 'linear',
position: 'bottom',
ticks: {
min: -1,
max: 8,
stepSize: 1,
fixedStepSize: 1,
}
}],
yAxes: [{
ticks: {
min: -2,
max: 4,
stepSize: 1,
fixedStepSize: 1,
}
}]
}
}
});
Here is a codepen example that demonstrates what this looks like

Chartjs 2 - Stacked bar and unstacked line on same chart with same y axis

I've started using the latest beta of v2 of chart.js since I need to draw a chart that contains both a stacked bar chart and an unstacked line chart on the same chart. Here's an example of what I need:
In this chart the lines are not stacked and are all showing their natural values but the bar chart is stacked and shows the combined total of the values (including some negative values).
I've managed to get the two charts drawn together but so far I've only succeeded in either having both charts stacked or I've had to use two separate y-axis which ends up with 2 scales. There's an example of the separate y-axis in this fiddle:
yAxes: [{
stacked: false,
ticks: {
beginAtZero: true
}
}, {
id: "bar-y-axis",
stacked: true,
ticks: {
beginAtZero: true
},
type: 'linear'
}]
If I remove the first y-axis then I ended up with a single scale with the only problem being that the line chart is now stacked as well.
Is there any way to draw a chart like I need using chart.js?

You can get this functionality with a combination of setting a different yAxisID (e.g. yAxisID: "bar-stacked") to each of your datasets, and then adding a second options.scales.yAxes object. So you would have this as a dataset:
{
label: 'Promoters',
backgroundColor: "#aad700",
yAxisID: "bar-stacked",
data: [
50, 44, 52, 62, 48, 58, 59, 50, 51, 52, 53, 54
]
}
and then you would add an additional yAxes (the first one will be the collection of your line datasets [no yAxisId in the example below], the second will be all of the bars you want stacked):
yAxes: [{
stacked: false,
ticks: {
beginAtZero: true,
min: 0,
max: 100
}
}, {
id: "bar-stacked",
stacked: true,
display: false, //optional if both yAxes use the same scale
ticks: {
beginAtZero: true,
min: 0,
max: 100
},
type: 'linear'
}]
Full example is as follows:
<!doctype html>
<html>
<head>
<title>Stacked Bar Chart</title>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.1.3/Chart.bundle.js"></script>
<style>
canvas {
-moz-user-select: none;
-webkit-user-select: none;
-ms-user-select: none;
}
</style>
</head>
<body>
<div style="width: 100%">
<canvas id="canvas"></canvas>
</div>
<script>
var barChartData = {
labels: ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"],
datasets: [{
data: [
50, 30, 60, 70, 80, 90, 95, 70, 90, 20, 60, 95
],
type: 'line',
label: 'This Year',
fill: false,
backgroundColor: "#fff",
borderColor: "#70cbf4",
borderCapStyle: 'butt',
borderDash: [],
borderDashOffset: 0.0,
borderJoinStyle: 'miter',
lineTension: 0.3,
pointBackgroundColor: "#fff",
pointBorderColor: "#70cbf4",
pointBorderWidth: 1,
pointHoverRadius: 5,
pointHoverBackgroundColor: "#70cbf4",
pointHoverBorderColor: "#70cbf4",
pointHoverBorderWidth: 2,
pointRadius: 4,
pointHitRadius: 10
}, {
data: [
25, 40, 30, 70, 60, 50, 40, 70, 40, 80, 30, 90
],
type: 'line',
label: 'Last Year',
fill: false,
backgroundColor: "#fff",
borderColor: "#737373",
borderCapStyle: 'butt',
borderDash: [10, 10],
borderDashOffset: 0.0,
borderJoinStyle: 'miter',
lineTension: .3,
pointBackgroundColor: "#fff",
pointBorderColor: "#737373",
pointBorderWidth: 1,
pointHoverRadius: 5,
pointHoverBackgroundColor: "#737373",
pointHoverBorderColor: "#737373",
pointHoverBorderWidth: 2,
pointRadius: 4,
pointHitRadius: 10
}, {
label: 'Promoters',
backgroundColor: "#aad700",
yAxisID: "bar-y-axis",
data: [
50, 44, 52, 62, 48, 58, 59, 50, 51, 52, 53, 54
]
}, {
label: 'Passives',
backgroundColor: "#ffe100",
yAxisID: "bar-y-axis",
data: [
20, 21, 24, 25, 26, 17, 28, 19, 20, 11, 22, 33
]
}, {
label: 'Detractors',
backgroundColor: "#ef0000",
yAxisID: "bar-y-axis",
data: [
30, 35, 24, 13, 26, 25, 13, 31, 29, 37, 25, 13
]
}]
};
window.onload = function() {
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: 'label'
},
responsive: true,
scales: {
xAxes: [{
stacked: true,
}],
yAxes: [{
stacked: false,
ticks: {
beginAtZero: true,
min: 0,
max: 100
}
}, {
id: "bar-y-axis",
stacked: true,
display: false, //optional
ticks: {
beginAtZero: true,
min: 0,
max: 100
},
type: 'linear'
}]
}
}
});
};
</script>
</body>
</html>

Another answer here - you can set a 'stack' identifier for the data you want to be cumulative (i.e. just the bars), and turn off 'fill' on the line graphs to draw just as a line rather than mountain range
Chart.js remove stacking

You can set the stacked property on bar datasets, so lines don't stack.
Try something like this:
data: {
datasets: [{
label: 'Line 1',
data: [],
backgroundColor: '#3788d8cc',
borderColor: '#3788d8cc',
fill: false
}, {
label: 'Stacked bar 1',
data: [],
backgroundColor: '#e51c23',
borderColor: '#e51c23',
type: 'bar',
stack: 'bar-stacked'
}, {
label: 'Line 2',
data: [],
backgroundColor: '#ff9800',
borderColor: '#ff9800',
fill: false
},
{
label: 'Stacked bar 2',
data: [],
type: 'bar',
backgroundColor: '#3f51b5',
borderColor: '#3f51b5',
stack: 'bar-stacked'
}],
labels: [],
},
options: {
maintainAspectRatio: false,
legend: {
display: true
},
scales: {
xAxes: [{
display: true
}],
yAxes: [{
display: true
}]
}
}