Bar Chart

A classic vertical bar chart showing fruit counts, taken from the Bokeh documentation. addDataNavigator is called after the chart renders with no manual structure configuration — the wrapper detects the bar chart pattern from the data shape.

Live example

Use keyboard navigation

What is happening

1. The wrapper marks the Bokeh container inert so screen readers skip the canvas.
2. A text-chat interface appears below the chart. Toggle Use keyboard navigation to switch to arrow-key navigation instead.
3. Type enter to begin navigating, then right / left to move between fruits.
4. onNavigate fires at every level — including the dimension root — so the chart can show a focus indicator as soon as navigation starts.
5. Type help at any time to see available commands.

Commands

Command	Action
enter	Enter the navigation structure
right	Move to the next fruit
left	Move to the previous fruit
move to <search>	Jump to a fruit by name
help	List available commands

Code Summary

import { addDataNavigator } from '@data-navigator/bokeh-wrapper';

const data = [
    { fruit: 'Apples', count: 5 },
    { fruit: 'Pears', count: 3 },
    { fruit: 'Nectarines', count: 4 },
    { fruit: 'Plums', count: 2 },
    { fruit: 'Grapes', count: 4 },
    { fruit: 'Strawberries', count: 6 }
];

const wrapper = addDataNavigator({
    plotContainer: '#my-plot',
    data,
    type: 'bar', // optional — auto-detected from data shape
    title: 'Fruit counts',
    xField: 'fruit',
    yField: 'count',
    compressSparseDivisions: true,
    onNavigate(node) {
        // onNavigate is when we draw our focus indicators (outlines)
        if (node.derivedNode && node.data?.fruit == null) {
            // Dimension root — no specific fruit yet; highlight the whole group.
            drawChart({ highlight: '__all__' });
        } else {
            drawChart({ highlight: node.data.fruit });
        }
    },
    onExit() {
        drawChart({ highlight: null });
    }
});

Full code

Create three files in the same directory and serve them with a local server (e.g. npx serve . or python -m http.server). Bokeh is loaded from CDN; the wrapper is loaded via import map. The wrapper tab is the integration layer; chart is the Bokeh rendering code.

wrapper.js

import { addDataNavigator } from '@data-navigator/bokeh-wrapper';
import { data, drawChart } from './chart.js';

let wrapper = null;
let highlightFruit = null;

function initWrapper(mode) {
    wrapper?.destroy();
    highlightFruit = null;
    drawChart({ highlightFruit });
    wrapper = addDataNavigator({
        plotContainer: 'bar-plot',
        chatContainer: 'bar-chat',
        mode,
        data,
        type: 'bar',
        title: 'Fruit counts',
        xField: 'fruit',
        yField: 'count',
        compressSparseDivisions: true,
        onNavigate(node) {
            if (node.derivedNode && node.data?.fruit == null) {
                highlightFruit = '__all__';
            } else {
                highlightFruit = node.data?.fruit ?? null;
            }
            drawChart({ highlightFruit });
        },
        onExit() {
            highlightFruit = null;
            drawChart({ highlightFruit });
        }
    });
}

initWrapper('text');

document.getElementById('bar-keyboard')?.addEventListener('change', e => {
    initWrapper(e.target.checked ? 'keyboard' : 'text');
});

chart.js

export const data = [
    { fruit: 'Apples', count: 5 },
    { fruit: 'Pears', count: 3 },
    { fruit: 'Nectarines', count: 4 },
    { fruit: 'Plums', count: 2 },
    { fruit: 'Grapes', count: 4 },
    { fruit: 'Strawberries', count: 6 }
];

export function drawChart({ highlightFruit = null } = {}) {
    const container = document.getElementById('bar-chart-inner');
    container.innerHTML = '';
    const plt = Bokeh.Plotting;
    const p = plt.figure({
        x_range: data.map(d => d.fruit),
        y_range: [0, 8],
        height: 300,
        width: 500,
        title: 'Fruit counts',
        toolbar_location: null,
        output_backend: 'svg'
    });

    p.vbar({
        x: data.map(d => d.fruit),
        top: data.map(d => d.count),
        bottom: 0,
        width: 0.8,
        color: data.map(d => (highlightFruit === '__all__' || d.fruit === highlightFruit ? '#1e3369' : '#aec7e8')),
        line_color: '#1e3369'
    });

    plt.show(p, '#bar-chart-inner');
}

index.html

<!doctype html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <title>Bar Chart — Data Navigator Bokeh Wrapper</title>
        <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/data-navigator/text-chat.css" />
        <script src="https://cdn.bokeh.org/bokeh/release/bokeh-3.7.3.min.js" crossorigin="anonymous"></script>
        <script src="https://cdn.bokeh.org/bokeh/release/bokeh-gl-3.7.3.min.js" crossorigin="anonymous"></script>
        <script src="https://cdn.bokeh.org/bokeh/release/bokeh-widgets-3.7.3.min.js" crossorigin="anonymous"></script>
        <script src="https://cdn.bokeh.org/bokeh/release/bokeh-api-3.7.3.min.js" crossorigin="anonymous"></script>
        <script type="importmap">
            {
                "imports": {
                    "@data-navigator/bokeh-wrapper": "https://esm.sh/@data-navigator/bokeh-wrapper",
                    "data-navigator": "https://esm.sh/data-navigator"
                }
            }
        </script>
    </head>
    <body>
        <div id="bar-plot" style="display:inline-block;">
            <div id="bar-chart-inner"></div>
        </div>
        <label>
            <input type="checkbox" id="bar-keyboard" />
            Use keyboard navigation
        </label>
        <div id="bar-chat" style="max-width:500px;"></div>
        <script type="module" src="./wrapper.js"></script>
    </body>
</html>