node-kernel

This module contains helper functions for node.js notebooks in Visual Studio Code.

This module unlocks the power of Notebooks in Visual Studio Code to provide rich outputs in node.js (i.e. you are no longer limited to plain text (console.log) outputs in node.js).

Tip: This npm package should be installed only if you require code completion within the node notebooks in Visual Studio Code (i.e. get intellisense for node-kernel when using node.js notebooks in Visual Studio Code).

Usage

Plain text, markdown, json output

const { display } = require('node-kernel');

// display plain text.
display.text('Plain text');

// display markdown.
display.markdown('Plain text');

// display markdown.
display.json({ data: 'some json' });

Html, Javascript output

// display html.
display.html('<h1>Hello</h1>');

// Or even more some interactive HTML.
const {display} = require('node-kernel');
const buttonText = 'Click me';
display.html(`
    <button id='myButton'>${buttonText}</button>
    <script type='text/javascript'>
    (() => {
        const btn = document.getElementById('myButton');
        btn.addEventListener("click", () => btn.innerText = 'You clicked the button');
    })();
    </script>
`);

// Include styles in HTML
const {display} = require('node-kernel');
display.html(`
    <style>
    #btn {
        color:red;
        background-color: yellow;
    }
    </style>
    <button id='btn'>Hello World</button>
`);

// Render output that will result in execution of javascript in the output.
dipslay.javascript(`
    document.getElementById('myButton').innerHTML = 'Updated button';
`);

Images output

const {display} = require('node-kernel');

// Render a base64 encoded string as an image
display.image('data:image/png;base64,iVBORw0KGgoAAAANSUhEU...');
// Render an svg string as an image
display.image('<svg width="250" height="15" ...');
// Render contents of a file as an image
display.image('/Users/..../sample.png');
// Render bytes as image
display.image(fs.readFileSync('/Users/..../sample.png'));

Plots (plotly): Generate & render

Built in support for plotly.

/**
 * Renders a plotly plot.
 * See detailed documentation here https://plotly.com/javascript/plotlyjs-function-reference/#plotlynewplot
 */
export function newPlot(
    root: plotly.Root,
    data: plotly.Data[],
    layout?: Partial<plotly.Layout>,
    config?: Partial<plotly.Config>
): Promise<void>;

// Generate Plots
const { Plotly } = require('node-kernel');
var data = [{
        values: [19, 26, 55],
        labels: ['Residential', 'Non-Residential', 'Utility'],
        type: 'pie'
    }];
var layout = {
    height: 400,
    width: 500
};
// If an HTML element named `myDiv` does not exist, the plot will be generated immdiately below the cell.
Plotly.newPlot('myDiv', data, layout);

Plots (plotly): Generate base64 string of the plot (useful if you want to embed this somewhere)

/**
 * Returns a base64 encoded string representation of the generated plot.
 * @param {plotly.Data[]} data See detailed documentation here https://plotly.com/javascript/plotlyjs-function-reference/#plotlynewplot
 * @param {plotly.Layout} layout See detailed documentation here https://plotly.com/javascript/plotlyjs-function-reference/#plotlynewplot
 * @param {('png' | 'svg' | 'jpeg')} [format] Defaults to 'png' if not specified.
 */
export function toBase64(
    data: plotly.Data[],
    layout: plotly.Layout,
    format?: 'png' | 'svg' | 'jpeg'
): Promise<string>;

Plots (plotly): Generate plot and save to a file.

/**
 * Saves the generated plot into a file.
 * Return the path to the file name (if a file path is not provided a temporary image file is created and returned).
 * @param {plotly.Data[]} data See detailed documentation here https://plotly.com/javascript/plotlyjs-function-reference/#plotlynewplot
 * @param {plotly.Layout} layout See detailed documentation here https://plotly.com/javascript/plotlyjs-function-reference/#plotlynewplot
 * @param {('png' | 'svg' | 'jpeg')} [format] Defaults to 'png' if not specified.
 * @param {string} [file] Destination file path for the image to be downloaded.
 * If not specified, the image is downloaded into a temporary file and that path is returned.
 * @return {*}  {Promise<string>}
 */
export function toFile(
    data: plotly.Data[],
    layout: plotly.Layout,
    format?: 'png' | 'svg' | 'jpeg',
    file?: string
): Promise<string>;