How to modify chartjs tooltip so i can add customized strings in tooltips

Question

How do i edit chartjs tooltip to add customized strings in tooltips

enter image description here

For Example: I want to change the Tooltip like "January: 28 Files" or just "28 Files"

there is a tooltip configuration HTML that is available as an option when you define the Global Configuration Options: http://www.chartjs.org/docs/#getting-started-global-chart-configuration — nicholaswmin, Sep 08 '14 at 12:10
@NicholasKyriakides didn't notice that. Now i can change the template tooltipTemplate: "<%if (label){%><%=label%>: <%}%><%= value %> Files" Thanks :) — Sudharshan, Sep 08 '14 at 12:17

score 11 · Accepted Answer · edited Sep 14 '15 at 23:40

11

Redefine default global tooltip template as follows:

Chart.defaults.global.tooltipTemplate =
  "<%if (label){%><%=label%>: <%}%><%= value %>";

Here is another example:

var ctx = document.getElementById("canvas").getContext("2d");

var myBarChart = new Chart(ctx).Bar(data, {
        tooltipTemplate: "<%= value %> Files"
});

edited Sep 14 '15 at 23:40

Dave Jarvis

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answered Sep 08 '14 at 12:24

Sudharshan

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27

This solution doesn't work for V2 of chart.js. If you are in trouble, please take a look to my answer or on this [link](http://stackoverflow.com/questions/34720530/chart-js-v2-add-prefix-or-suffix-to-tooltip-label) – Apr 28 '17 at 09:21

score 4 · Answer 2 · answered Nov 10 '21 at 11:40

The great previous answers do not work with chartjs 3. This example is from the official documentation:

const chart = new Chart(ctx, {
type: 'line',
data: data,
options: {
    plugins: {
        tooltip: {
            callbacks: {
                label: function(context) {
                    const label = context.dataset.label || '';

                    if (label) {
                        label += ': ';
                    }
                    if (context.parsed.y !== null) {
                        label += new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' }).format(context.parsed.y);
                    }
                    return label;
                }}}}}});

John Bonfardeci · Answer 3 · 2020-11-21T17:19:13.560

Drawing from other responses I've found that helped me, apparently the label properties can be set to functions, For example, to format currency:

var overrides = {
  // show lables as currency
  scaleLabel: toCurrency,

  // String - Template string for single tooltips
  tooltipTemplate: toCurrency,

  // String - Template string for multiple tooltips
  multiTooltipTemplate: toCurrency
}

function toCurrency(label) {
    return '$' + label.value.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
}

How to modify chartjs tooltip so i can add customized strings in tooltips

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