Publish Vega visualizations as embedded web components with interactive parameters.
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Latest commit 6efecd4 Jul 16, 2018

README.md

Vega-Embed

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Vega-Embed makes it easy to embed interactive Vega and Vega-Lite views into web pages. With Vega Embed, you can:

  • Load Vega/Vega-Lite specs from source text, parsed JSON, or URLs.
  • Add action links such as "View Source" and "Open in Vega Editor".
  • Includes Vega Tooltip.
  • Includes Vega Themes. Experimental: themes are not stable yet

Vega-Lite works well with Observable. Learn how to use it in our example notebook.

Basic Example

You can import Vega-Embed from a local copy or (as shown below) from jsDelivr. Please replace [VERSION] with the correct Vega, Vega-Lite, and Vega-Embed versions. We recommend that you specify the major versions (vega@4, vega-lite@2, vega-embed@3).

<!DOCTYPE html>
<html>
<head>
  <!-- Import Vega 4 & Vega-Lite 2 (does not have to be from CDN) -->
  <script src="https://cdn.jsdelivr.net/npm/vega@[VERSION]"></script>
  <script src="https://cdn.jsdelivr.net/npm/vega-lite@[VERSION]"></script>
  <!-- Import vega-embed -->
  <script src="https://cdn.jsdelivr.net/npm/vega-embed@[VERSION]"></script>
</head>
<body>

<div id="vis"></div>

<script type="text/javascript">
  var spec = "https://raw.githubusercontent.com/vega/vega/master/docs/examples/bar-chart.vg.json";
  vegaEmbed('#vis', spec).then(function(result) {
    // Access the Vega view instance (https://vega.github.io/vega/docs/api/view/) as result.view
  }).catch(console.error);
</script>
</body>
</html>

Look at an example online at Vega-Embed Block.

API Reference

The default export of Vega-Embed is a wrapper function that automatically chooses between embed and container based on the provided arguments.

# embed(el, spec[, opt]) <>

Returns a Promise that resolves to the instantiated Vega View instance and a copy of the parsed JSON Vega spec. The embed function accepts the following arguments:

Property Type Description
el String A DOM element or CSS selector indicating the element on the page in which to add the embedded view.
spec String / Object String : A URL string from which to load the Vega specification. This URL will be subject to standard browser security restrictions. Typically this URL will point to a file on the same host and port number as the web page itself.
Object : The Vega/Vega-Lite specification as a parsed JSON object.
opt     Object   (Optional) A JavaScript object containing options for embedding.

Note: Internet Explorer does not support the ES6 Promise feature. To make it work correctly, please follow the instructions on the Vega website.

# container(spec[, opt]) <>

Returns a Promise* that resolves to an HTML element with the Vega View instance as the value property. The function is designed to work with Observable. The container function accepts the following arguments:

Property Type Description
spec String / Object String : A URL string from which to load the Vega specification. This URL will be subject to standard browser security restrictions. Typically this URL will point to a file on the same host and port number as the web page itself.
Object : The Vega/Vega-Lite specification as a parsed JSON object.
opt     Object   (Optional) A JavaScript object containing options for embedding.

Options

var opt = {
  "mode": ...,

  "theme": ...,
  "defaultStyle": ...,

  // view config options
  "renderer" : ...,
  "loader" : ...,
  "logLevel" : ...,

  "tooltip": : ...,

  "onBeforeParse" : ...,

  "width" : ...,
  "height" : ...,
  "padding" : ...,

  "actions" : {
    "export": ...,
    "source": ...,
    "compiled": ...,
    "editor": ...
  },

  "scaleFactor": ...,

  "config"  : ...,

  "editorUrl": ...,

  "sourceHeader" : ...,
  "sourceFooter": ...,

  "hover" : ...,

  "runAsync": ...,

  "i18n": {
    "COMPILED_ACTION": ...,
    "EDITOR_ACTION": ...,
    "PNG_ACTION": ...,
    "SOURCE_ACTION": ...,
    "SVG_ACTION": ...
  }
}
Property Type Description
mode String If specified, tells Vega-Embed to parse the spec as vega or vega-lite. Vega-Embed will parse the $schema url if the mode is not specified. Vega-Embed will default to vega if neither mode, nor $schema are specified.
theme String If specified, tells Vega-Embed use the theme from Vega Themes. Experimental: we may update themes with minor version updates of Vega-Embed.
defaultStyle Boolean or String Add default stylesheet for embed actions.
renderer String The renderer to use for the view. One of "canvas" (default) or "svg". See Vega docs for details.
logLevel Level Sets the current log level. See Vega docs for details.
tooltip Handler or Boolean or Object Provide a tooltip handler, customize the default Vega Tooltip handler, or disable the default handler.
loader Loader / Object Loader : Sets a custom Vega loader. Object : Vega loader options for a loader that will be created.
See Vega docs for details.
onBeforeParse Function A callback function that can modify an input specification before it is parsed.
width Number Sets the view width in pixels. See Vega docs for details. Note that Vega-Lite overrides this option.
height Number Sets the view height in pixels. See Vega docs for details. Note that Vega-Lite overrides this option.
padding Object Sets the view padding in pixels. See Vega docs for details.
actions Boolean / Object Determines if action links ("Export as PNG/SVG", "View Source", "View Vega" (only for Vega-Lite), "Open in Vega Editor") are included with the embedded view. If the value is true, all action links will be shown and none if the value is false. This property can take a key-value mapping object that maps keys (export, source, compiled, editor) to boolean values for determining if each action link should be shown. By default, export, source, and editor are true and compiled is false. These defaults can be overridden: for example, if actions is {export: false, source: true}, the embedded visualization will have two links – "View Source" and "Open in Vega Editor". The export property can take a key-value mapping object that maps keys (svg, png) to boolean values for determining if each export action link should be shown. By default, svg and png are true.
scaleFactor Number The number by which to multiply the width and height (default 1) of an exported PNG or SVG image.
config String / Object String : A URL string from which to load a Vega/Vega-Lite or Vega-Lite configuration file. This URL will be subject to standard browser security restrictions. Typically this URL will point to a file on the same host and port number as the web page itself.
Object : A Vega/Vega-Lite configuration as a parsed JSON object to override the default configuration options.
editorUrl String The URL at which to open embedded Vega specs in a Vega editor. Defaults to "http://vega.github.io/editor/". Internally, Vega-Embed uses HTML5 postMessage to pass the specification information to the editor.
sourceHeader String HTML to inject into the `` tag of the page generated by the "View Source" and "View Vega" action link. For example, this can be used to add code for syntax highlighting.
sourceFooter String HTML to inject into the end of the page generated by the "View Source" and "View Vega" action link. The text will be added immediately before the closing `` tag.
hover Boolean Enable hover event processing.
runAsync Boolean Use runAsync instead of run.
i18n Object This property maps keys (COMPILED_ACTION, EDITOR_ACTION, PNG_ACTION, SOURCE_ACTION, SVG_ACTION) to string values for the action's text. By default, the text is in English.

Common questions

How do I send cookies when loading data?

By default, the Vega loader does not send the credentials of the current page with requests. You can override this behavior by passing {loader: { http: { credentials: 'same-origin' }}} as the embed option.

Build Process

To build vega-embed.js and view the test examples, you must have yarn installed.

  1. Run yarn in the Vega-Embed folder to install dependencies.
  2. Run yarn build. This will create vega-embed.js and the minified vega-embed.min.js.
  3. Run a local webserver with yarn start then point your web browser at the test page (e.g., http://localhost:8000/test-vg.html(Vega) or http://localhost:8000/test-vl.html(Vega-Lite)).

Release Process

To release a new version, make sure that everything works. Then run yarn version and bump the version number. Lastly, push to GitHub (with the release tag). Travis will build a bundle and make the npm release automatically.