Interactions

By default, these options apply to both the hover and tooltip interactions. The same options can be set in the options.hover namespace, in which case they will only affect the hover interaction. Similarly, the options can be set in the options.plugins.tooltip namespace to independently configure the tooltip interactions.

The following properties define how the chart interacts with events. Namespace: options

For example, to have the chart only respond to click events, you could do:

Events for each plugin can be further limited by defining (allowed) events array in plugin options:

const chart = new Chart(ctx, {
  type: 'line',
  data: data,
  options: {
    // All of these (default) events trigger a hover and are passed to all plugins,
    // unless limited at plugin options
    events: ['mousemove', 'mouseout', 'click', 'touchstart', 'touchmove'],
    plugins: {
      tooltip: {
        events: ['click']
      }
    }
  }
});

Events that do not fire over chartArea, like mouseout, can be captured using a simple plugin:

const chart = new Chart(ctx, {
  type: 'line',
  data: data,
    // these are the default events:
    // events: ['mousemove', 'mouseout', 'click', 'touchstart', 'touchmove'],
  },
  plugins: [{
    id: 'myEventCatcher',
    beforeEvent(chart, args, pluginOptions) {
      const event = args.event;
      if (event.type === 'mouseout') {
        // process the event
      }
    }
  }]
});

Converting Events to Data Values

A common occurrence is taking an event, such as a click, and finding the data coordinates on the chart where the event occurred. Chart.js provides helpers that make this a straightforward process.

Modes

When configuring the interaction with the graph via interaction, hover or tooltips, a number of different modes are available.

options.hover and options.plugins.tooltip extend from options.interaction. So if mode, intersect or any other common settings are configured only in options.interaction, both hover and tooltips obey that.

The modes are detailed below and how they behave in conjunction with the intersect setting.

Finds all of the items that intersect the point.

const chart = new Chart(ctx, {
    type: 'line',
    data: data,
    options: {
        interaction: {
            mode: 'point'
        }
    }
});

nearest

const chart = new Chart(ctx, {
    type: 'line',
    data: data,
    options: {
        interaction: {
            mode: 'nearest'
    }
});

Finds item at the same index. If the intersect setting is true, the first intersecting item is used to determine the index in the data. If intersect false the nearest item, in the x direction, is used to determine the index.

To use index mode in a chart like the horizontal bar chart, where we search along the y direction, you can use the axis setting introduced in v2.7.0. By setting this value to 'y' on the y direction is used.

const chart = new Chart(ctx, {
    type: 'bar',
    data: data,
    options: {
        interaction: {
            mode: 'index',
            axis: 'y'
        }
    }
});

dataset

Finds items in the same dataset. If the intersect setting is true, the first intersecting item is used to determine the index in the data. If intersect false the nearest item is used to determine the index.

const chart = new Chart(ctx, {
    type: 'line',
    data: data,
    options: {
        interaction: {
            mode: 'dataset'
        }
    }
});

Returns all items that would intersect based on the X coordinate of the position only. Would be useful for a vertical cursor implementation. Note that this only applies to cartesian charts.

y

Returns all items that would intersect based on the Y coordinate of the position. This would be useful for a horizontal cursor implementation. Note that this only applies to cartesian charts.

const chart = new Chart(ctx, {
    type: 'line',
    data: data,
    options: {
        interaction: {
            mode: 'y'
        }
});