Develop Reference

How do remove the bottom scale on a Chart.js bar chart

I'm using Chart.js to create the following chart:
The issue is that I want to make the scale at the bottom only show 0 and the maximum number (here being 12).
JavaScript:
<script>
new Chart(document.getElementById("leads-bar"), {
type: 'horizontalBar',
data: {
labels: ["Hot", "Warm", "Cold"],
datasets: [
{
backgroundColor: ["#d23232", "#ff9347", "#bbbbbb"],
data: [7, 9, 11]
}
]
},
options: {
legend: {
display: false
},
tooltips: {
display: false
},
title: {
display: false
},
scales: {
xAxes: [{
stacked: true,
gridLines: {
display: false,
drawBorder: false,
},
scaleShowLabels: false,
}],
yAxes: [{
stacked: false,
gridLines: {
color: ["#eeeeee"]
}
}]
}
}
});

var dataArr = [154.23, 203.21, 429.01, 637.41];
var chart = new Chart(ctx, {
type: 'horizontalBar',
data: {
labels: [154.23, 203.21, 429.01, 637.41],
datasets: [{
label: 'LINE',
data: dataArr,
backgroundColor: 'rgba(0, 119, 290, 0.2)',
borderColor: 'rgba(0, 119, 290, 0.6)',
fill: false,
tension: 0
}]
},
options: {
scales: {
xAxes: [{
ticks: {
min: Math.min.apply(this, dataArr),
max: Math.max.apply(this, dataArr),
callback: function(value, index, values) {
if (index === values.length - 1) return Math.min.apply(this, dataArr);
else if (index === 0) return Math.max.apply(this, dataArr);
else return '';
}
}
}]
}
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.6.0/Chart.min.js"></script>
<canvas id="ctx"></canvas>

Chart.js Mouse Over Show Old Chart Data

I was having some problem when trying to redraw chart on canvas using chart.js in Angular. Here is my HTML component:
<div class="form-group">
<select [(ngModel)]="timeMode" id="timeModeInput" class="browser-default custom-select" (change)="onTimeModeChange($event)">
<option value="all" selected>Yearly</option>
<option value="monthly">Monthly</option>
</select>
</div>
<canvas id="expenseTimelineCanvas"></canvas>
Upon dropdown select, I repopulate the chart:
if (chart != null) { chart.destroy(); chart.clear(); }
chart = new Chart(chartName, {
type: "line",
data: {
labels: labels,
datasets: [
{
data: chartData,
borderColor: lineColor,
fill: false,
borderWidth: 1,
borderDash: [10, 10],
pointBackgroundColor: "white",
pointBorderColor: lineColor,
pointRadius: 5
}
]
}
}
});
However, when I mouse over at certain part of the canvas, the old chart will be displayed. Any ideas on how to totally destroy the canvas before replotting on the same DOM element?
Thanks!

this happens because chartjs uses canvas and for redrawing you just have to destroy old drawing from the canvas.
when you make a new chart then you have to destroy the old chart.
but in angular you can also just reload the component to destroy the chart
your method
//this method
initChart(){
//this will generate chart you need
//before generating just destroy the old chart
}
second method
//in html file
<thisIsHTMLTagOfChartComponent *ngIf="showChart">
</thisIsHTMLTagOfChartComponent>
//in typescript
public showChart = false;
//this function will be called everytime you fetch the data from server
getChartData(){
this.showChart = false; //this will remove the component from the page
fetchData(uri)
.then(result => {
//do your stuff here
this.showChart = true // this will load the component in the page again
}
)

i prefer to not destroy your chart just change the value of it for e.g: in your change function just load a new chart definition in your same chart with new config, we have 2 different configs:
config = {
type: 'bar',
data: {
labels: dringlichkeiten.map(x => x.id),
datasets: [
{
label: 'My Bar Chart',
data: dringlichkeiten.map(x => x.value),
backgroundColor: ['red', 'green', 'yellow', 'blue', 'orange']
}
]
},
}
config2 = {
type: 'line',
data: {
datasets: [{
label: 'Höhenlinie',
backgroundColor: "rgba(255, 99, 132,0.4)",
borderColor: "rgb(255, 99, 132)",
fill: true,
data: [
{ x: 1, y: 2 },
{ x: 2500, y: 2.5 },
{ x: 3000, y: 5 },
{ x: 3400, y: 4.75 },
{ x: 3600, y: 4.75 },
{ x: 5200, y: 6 },
{ x: 6000, y: 9 },
{ x: 7100, y: 6 },
],
}]
},
options: {
responsive: true,
title: {
display: true,
text: 'Höhenlinie'
},
scales: {
xAxes: [{
type: 'linear',
position: 'bottom',
ticks: {
userCallback: function (tick) {
if (tick >= 1000) {
return (tick / 1000).toString() + 'km';
}
return tick.toString() + 'm';
}
},
scaleLabel: {
labelString: 'Länge',
display: true,
}
}],
yAxes: [{
type: 'linear',
ticks: {
userCallback: function (tick) {
return tick.toString() + 'm';
}
},
scaleLabel: {
labelString: 'Höhe',
display: true
}
}]
}
}
}
chart: Chart ;
in your change function just load a new config:
change(){
this.chart = new Chart('canvas', this.config2)
}
DEMO.

Does the min value of the xAxes have to be within the dataset

I'm trying to add the ability to change a 'date' range for my chart, and I've added a button callback that changes the min value of the xAxes and then calls chart.update(), but the chart doesn't change.
I've tried manually entering a number, and unless it's a value in the data given for the table it won't update the graph.
this.analysisChart = new Chart(context, {
// The type of chart we want to create
type: 'line',
// The data for our dataset
data: {
labels: calculations.rollingTimestamps,
datasets: [
{
label: 'Cycle Times',
data: calculations.rollingCycleTimesXY,
borderColor: 'rgb(0,255,0,1)',
backgroundColor: 'rgb(0,255,0,0.5)',
type: 'scatter',
showLine: false,
labels: calculations.rollingAliases
},
{
label: 'Rolling μ',
borderColor: 'rgb(255, 99, 132, 1)',
backgroundColor: 'rgb(255, 99, 132, 0.5)',
data: calculations.rollingAverage,
fill: false,
pointRadius: 0
},
{
label: 'Overall μ',
data: calculations.overallAverageArr,
fill: false,
borderColor: 'rgb(0,0,0,1)',
backgroundColor: 'rgb(0,0,0,0.5)',
pointRadius: 0,
showLine: true
},
{
label: 'μ + σ',
data: calculations.rollingMaxStandardDeviation,
fill: 4,
backgroundColor: 'rgb(50,50,255,0.35)',
borderColor: 'rgb(50,50,255,0)',
pointRadius: 0,
showLine: true
},
{
label: 'μ - σ',
data: calculations.rollingMinStandardDeviation,
fill: 3,
backgroundColor: 'rgb(50,50,255,0.35)',
borderColor: 'rgb(50,50,255,0)',
pointRadius: 0,
showLine: true
},
{
label: 'μ + 2 * σ',
data: calculations.rollingMaxSecondStandardDeviation,
fill: 3,
backgroundColor: 'rgb(50,50,255,0.3)',
borderColor: 'rgb(50,50,255,0)',
pointRadius: 0,
showLine: true
},
{
label: 'μ - 2 * σ',
data: calculations.rollingMinSecondStandardDeviation,
fill: 4,
backgroundColor: 'rgb(50,50,255,0.3)',
borderColor: 'rgb(50,50,255,0)',
pointRadius: 0,
showLine: true
}
]
},
// Configuration options go here
options: {
layout: {
padding: {
left: 20,
right: 20,
top: 0,
bottom: 0
}
},
tooltips: {
mode: 'index',
intersect: false,
callbacks: {
label: function(tooltipItem, data) {
var label = data.datasets[tooltipItem.datasetIndex].label || '';
if (label) {
label += ': ';
}
label += Math.round(tooltipItem.yLabel * 10) / 10;
return label + " days";
}
}
},
hover: {
mode: 'index',
intersect: false
},
scales: {
yAxes: [{
ticks: {
min: 0,
type: 'linear',
callback: function(label, index, labels) {
return label + " days";
}
}
}],
xAxes: [{
ticks: {
type: 'linear',
min: 0,
callback: function(label, index, labels) {
return new Date(label).toDateString();
}
}
}]
},
title: {
display: true,
text: 'Cycle Times'
}
}
});
What I'd like to do is give an arbitrary number and have it perform a greater than check across the data for determining what to cut off rather than doing a find and then cutting anything off that is after that index in the array.
How can I do this?

As a solution, I just wrote a function to iterate through the array and find the first value that is greater than or equal to the value I wanted and then set the min of the xAxes to that value. Not very ideal, but hey at least it works.
I couldn't find anything in the documentation about callbacks for the min value.

How to edit my custom tooltips in my line chart using chart.js?

This is my code
var ctx = document.getElementById("myChart").getContext('2d');
var myChart = new Chart(ctx, {
type: 'line',
data: {
labels: [{{ $nDate }}],
datasets: [{
label: 'All Users',
data: [ {{ $nUser }} ],
backgroundColor: ['rgba(54, 162, 235, 0.2)'],
borderColor: ['rgba(54, 162, 235, 1)'],
borderWidth: 3,
lineTension: 0,
labelFontSize : '16',
}]
},
options: {
tooltips: {
mode: 'index',
intersect: false,
position: 'nearest'
},
responsive: false,
legend: { display: false },
scales: {
yAxes: [{
ticks: {
beginAtZero:true,
type: 'category',
labelOffset: 10,
stepSize:250,
callback: function(value, index) {
if (value !== 0) return value;
}
},
gridLines:{
drawBorder:false
}
}],
xAxes: [{
gridLines: {
display: false,
},
}],
},
plugins:{
datalabels:{
display:false
}
}
}
});
My output
My Expected Output
How can I able to put/edit custom tooltip in my line chart? I just want to get the exact tooltips in the second picture but I don't have any idea how to fix it? Another thing is my $nDateI only want to show four dates like 8,15,22,29 But when I tried to create a new array label with value of this [" ", " "]; my chart crashed.

You can use custom callback function to render with your own choice html tags and colors, Follow the official documentation link for further guidance.
http://www.chartjs.org/docs/latest/configuration/tooltip.html#external-custom-tooltips
options: {
tooltips: {
enabled: false,
custom: function(tooltipModel) {}
}
}

Chart.JS Can not read property '_meta' of Undefined

I am attempting to build a basic bar chart, but I am getting the error in the title. I have used alert() to verify that the array I want to populate the chart with holds data, but something is still not fishing out properly with the syntax. Can someone examine and let me know what I need to do better in order to make the chart produce?
var ctx = document.getElementById('cvtree').getContext('2d');
var chart = new Chart(ctx, {
type: 'bar',
data: {
labels: yoylabels,
datasets: [{
label: 'Pay By Person',
backgroundColor: 'rgba(0, 129, 214, 0.8)',
data: numericdollarvals
}]
},
options: {
},
legend: {
display: false,
position: 'top',
},
scales: {
yAxes: [{
ticks: {
beginAtZero: true,
callback: function (value, index, values) {
if (parseInt(value) >= 1000) {
return '$' + value.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
} else {
return '$' + value;
}
}
}
}]
}
});

You are unexpectedly closing off the options property, before setting all the options.
Here is the correct syntax :
var ctx = document.getElementById('cvtree').getContext('2d');
var chart = new Chart(ctx, {
type: 'bar',
data: {
labels: yoylabels,
datasets: [{
label: 'Pay By Person',
backgroundColor: 'rgba(0, 129, 214, 0.8)',
data: numericdollarvals
}]
},
options: {
legend: {
display: false,
position: 'top',
},
scales: {
yAxes: [{
ticks: {
beginAtZero: true,
callback: function(value, index, values) {
if (parseInt(value) >= 1000) {
return '$' + value.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
} else {
return '$' + value;
}
}
}
}]
}
}
});