html-sketchapp-cli

Quickly generate Sketch libraries from HTML documents and living style guides, powered by html-sketchapp and Puppeteer.

Add some simple markup to your page, for example:

<div data-sketch-symbol="Button/Primary">...</div>
<div data-sketch-text="Heading">...</div>
<div data-sketch-color="#212121">...</div>

Then run the html-sketchapp command to generate JSON files in html-sketchapp's "Almost Sketch" format, ready to be imported into Sketch.

$ html-sketchapp --file sketch.html --out-dir dist/sketch

Install

Please note: html-sketchapp-cli requires Node.js and targets the latest "Active LTS" version. Older versions of Node are unsupported.

If you're in a hurry and just want to try it out, you can install html-sketchapp-cli globally, along with html-sketchapp's Sketch plugin:

$ npm install --global html-sketchapp-cli
$ html-sketchapp install

However, when using html-sketchapp-cli in the context of a project, you should install it locally instead:

$ npm install --save-dev html-sketchapp-cli

Then, add some scripts to your package.json:

{
  "scripts": {
    "html-sketchapp-install": "html-sketchapp install",
    "html-sketchapp": "html-sketchapp [...args]"
  }
}

Once these scripts have been added, the following commands can be run within your project:

$ npm run html-sketchapp-install
$ npm run html-sketchapp

Page Setup

Before using this tool, you'll need to add some hooks to your page so that everything can be selected, extracted and named correctly.

Annotate symbols with data-sketch-symbol attributes. Note that forward slashes will create nested menu items within Sketch.

<div data-sketch-symbol="Button/Primary">
  ...
</div>

Annotate nested symbols with data-sketch-symbol-instance attributes, where the attribute values reference existing symbols defined elsewhere in the document.

<div data-sketch-symbol="Icon/Reply">...</div>
<div data-sketch-symbol="Icon/Retweet">...</div>
<div data-sketch-symbol="Icon/Like">...</div>
 
<div data-sketch-symbol="IconRow">
  <div data-sketch-symbol-instance="Icon/Reply">...</div>
  <div data-sketch-symbol-instance="Icon/Retweet">...</div>
  <div data-sketch-symbol-instance="Icon/Like">...</div>
</div>

Annotate all text styles with data-sketch-text attributes.

<div data-sketch-text="Heading">
  ...
</div>

Annotate all colors with data-sketch-color attributes. Note that colors are unnamed in Sketch, so only the hex value needs to be provided.

<div data-sketch-color="#212121">
  ...
</div>

For a real world example, check out SEEK Style Guide's sketch exports page and the corresponding source code.

CLI Usage

Importing from a local file

If your page is self-contained, you can import from a local HTML file.

$ html-sketchapp --file sketch.html --out-dir dist

Importing from a local static web server

If your page needs to be hosted on a static web server, you can provide a local directory to serve and a root relative URL to import from.

$ html-sketchapp --serve docs --url /sketch --out-dir dist

Importing from existing web server

If your page is hosted on an existing web server, you can provide an absolute URL.

$ html-sketchapp --url http://localhost:3000 --out-dir dist

Viewport sizes and responsive design

If you provide a set of one or more named viewports, every symbol and text style will be rendered for each screen size.

$ html-sketchapp --viewports.Desktop 1024x768 --viewports.Mobile 320x568 --file sketch.html --out-dir dist

If multiple screen sizes are provided, the viewport name will be being appended to all symbol and text style names. For example, Button/Primary will be exported as Button/Primary/Desktop and Button/Primary/Mobile.

Optionally, you can set the pixel density for a given viewport by adding an @ followed by the desired scaling factor to the end of the viewport's resolution. For example, you can simulate a 1.5x and 2x display like so:

$ html-sketchapp --viewports.HigherDensity 1024x768@1.5 --viewports.Retina 1024x768@2 --file sketch.html --out-dir dist

If no scaling factor is provided, a default of 1 will be used.

Config file

All options can be provided via an html-sketchapp.config.js file.

module.exports = {
  file: 'sketch.html',
  outDir: 'dist/sketch',
  viewports: {
    Desktop: '1024x768',
    Mobile: '320x568'
  },
  puppeteerArgs: '--no-sandbox --disable-setuid-sandbox',
  puppeteerExecutablePath: 'google-chrome-unstable'
};

You can provide an alternate config file path with the --config option.

$ html-sketchapp --config example.config.js

Importing into Sketch

Once this command has successfully run, the following files will be generated in the output directory.

• document.asketch.json
• page.asketch.json

These need to be imported into Sketch via html-sketchapp's corresponding Sketch plugin. To ease the install process, you can run the following command.

$ html-sketchapp install

Then, open a new Sketch document and, from the menu, select Plugins > From *Almost* Sketch to Sketch. In the file picker, select both document.asketch.json and page.asketch.json, and click Choose.

Congratulations! You should now have your symbols, text styles and document colors available within Sketch! 💎🎉

Advanced Usage

Debug mode

If you need to see what Puppeteer is doing, you can provide the --debug flag which will do the following things:

• Turn off headless mode
• Bring the browser window to the front
• Forward console calls to the terminal
• Stop the browser from closing until you exit the CLI tool

For example:

$ html-sketchapp --url http://localhost:3000 --out-dir dist --debug

Puppeteer args

If you need to provide command line arguments to the browser instance via Puppeteer, you can provide the puppeteer-args option.

Since Puppeteer uses Chromium internally, you can refer to the List of Chromium Command Line Switches for available options.

For example, if you'd like to disable the browser sandbox:

$ html-sketchapp --puppeteer-args="--no-sandbox --disable-setuid-sandbox" --file sketch.html --out-dir dist

Note: Because Puppeteer args are prefixed with hyphens, you must use an equals sign and quotes when providing this option via the command line (as seen above).

Puppeteer waitUntil

By default, Puppeteer is configured to consider the page loaded when there are no more than 2 network connections for at least 500ms (networkidle2). This is so that html-sketchapp-cli can handle development environments with long-lived connections.

If the page you're requesting has 2 or fewer resources that stall for longer than 500ms and doesn't complete loading, you can switch back to networkidle0 via the puppeteer-wait-until argument:

$ html-sketchapp --puppeteer-wait-until networkidle0 --file sketch.html --out-dir dist

For the full list of available options for waitUntil, view the Puppeteer page.goto() API documentation.

Chromium executable

If you'd like to override the Chromium used by Puppeteer, you can provide a path to the executable with the puppeteer-executable-path option.

$ html-sketchapp --puppeteer-executable-path google-chrome-unstable --file sketch.html --out-dir dist

Middleware

If you need to call out to lower-level html-sketchapp APIs, you can provide middleware functions that allow you to modify the underlying Sketch classes as they're generated.

It's recommended that you provide middleware via a config file as inline functions, for example:

module.exports = {
  symbolLayerMiddleware: (args) => { ... }
};

Alternatively, you can also provide middleware as standalone JavaScript files, configured via the command line:

$ html-sketchapp --symbol-layer-middleware symbol.layer.middleware.js

This assumes that your middleware is a JavaScript module that exports the function:

module.exports = (args) => { ... };

However, in order to keep the documentation streamlined, all examples will use the config file notation.

Symbol Layer Middleware

This middleware is executed for every layer within a symbol.

The typical use case for this is html-sketchapp's layer.setResizingConstraint API which allows you to configure how a layer should behave when a symbol is resized.

module.exports = {
  symbolLayerMiddleware: args => { ... }
};

The following arguments are passed into your middleware function:

• layer: the html-sketchapp layer instance
• SVG: The SVG class for type checking of layer
• Text: The Text class for type checking of layer
• Rectangle: The Rectangle class for type checking of layer
• ShapeGroup: The ShapeGroup class for type checking of layer
• RESIZING_CONSTRAINTS: Object containing constants for the setResizingConstraint API

For example, when handling SVGs differently from other layers:

module.exports = {
  symbolLayerMiddleware: (args) => {
    const { layer, SVG, RESIZING_CONSTRAINTS } = args;
 
    layer.setResizingConstraint(RESIZING_CONSTRAINTS.LEFT, RESIZING_CONSTRAINTS.TOP);
 
    if(layer instanceof SVG) {
      layer.setResizingConstraint(RESIZING_CONSTRAINTS.TOP, RESIZING_CONSTRAINTS.LEFT, RESIZING_CONSTRAINTS.WIDTH, RESIZING_CONSTRAINTS.HEIGHT);
    }
  }
};
 

Symbol Middleware

This middleware is executed for every symbol within a document.

module.exports = {
  symbolMiddleware: args => { ... }
};

The following arguments are passed into your middleware function:

• symbol: The current symbol master
• node: The source HTML node
• suffix: The symbol name suffix (e.g. /Desktop)
• RESIZING_CONSTRAINTS: Object containing constants for the setResizingConstraint API

Symbol Instance Middleware

This middleware is executed for every symbol instance within a document.

module.exports = {
  symbolInstanceMiddleware: args => { ... }
};

The following arguments are passed into your middleware function:

• symbolInstance: The current symbol instance
• symbolMaster: The symbol master that the symbol instance is referencing
• node: The source HTML node
• RESIZING_CONSTRAINTS: Object containing constants for the setResizingConstraint API

Contributing

Refer to CONTRIBUTING.md.

License

MIT.