This utility makes it easier to creating your own Sass theme for ArcGIS API for JavaScript applications.

By working with Sass, you no longer need to figure out CSS overrides by brute-force, which is brittle and not scalable.

• node/npm
• Working knowledge of Sass is highly recommended

• npm install
• npm run setup- sets up the development environment, which will lay out the Sass theme files. Be careful, this command will override any changes to my-theme/main.scss.
• npm start - launches a preview page that will automatically reload when making changes.

The following is a simplified look at the styles folder structure:

sass/
  +-- base/
  |   +-- colors/
  |   +-- fonts/
  |   +-- icons/
  |   +-- images/
  |   +-- widgets/
  |
  +-- examples/
  |
  +-- my-theme/
      |
      +-- main.scss

• base/ contains the foundation for all themes. Here is where we define variables, functions, mixins, and other helpers, such as color, font, and icon resources.

• examples/ contains examples for different themes provided in the ArcGIS API for JavaScript.

• my-theme/ contains your custom theme's main file.

Under my-theme/ you will find main.scss. This file already imports the core for your theme, so the simplest way to start customizing is to to define variable overrides.

/*
  Theme: My Theme
*/

// variable overrides
$some_variable_to_override : <overridden value>;

// import theme base
@import "../base/core";

If you want more control, you can also create the theme to your liking and import any dependencies from base as needed.

@import "../base/mixins";  // mixins are now available for use

// custom scss goes here

By default _core.scss will include all widget styles. You can make the distributable theme leaner by excluding widget styles. Each widget has a corresponding variable that controls whether they are included in the theme or not. Set these to false for anything you want to exclude.

// exclude non-default widgets
$include_BasemapToggle    : false;
$include_ColorPicker      : false;
$include_HorizontalSlider : false;
$include_Legend           : false;
$include_RendererSlider   : false;
$include_Ripple           : false;
$include_Search           : false;
$include_Tags             : false;

// import theme base
@import "../base/core";

ArcGIS API for JavaScript v4.10 made improvements to the way Sass files were structured. These changes were made to improve consistency and make names more semantic (by applying BEM naming convention).

The following lists the main changes that may affect your code:

• Underscores _ have been replaced by dashes -.

• "text" is now "font" (e.g., $text_size is now $font-size)
• font size usage terms are now treated as a BEM Element
  • $h1_text_size is now $font-size__h1
  • $body_text_size is now $font-size__body
• For a smaller font size not related to an element, use $font-size--small
• Added $base-font-size
  • All font sizes are based on $base-font-size
    • e.g. $font-size__h1: round($base-font-size * 1.428)
• Font weights
  • $text_weight_normal is now simply $font-weight
  • Use $font-weight__heading for headings ("header" was incorrectly used before)
  • For a bold font weight not related to a heading, use $font-weight__bold

• Using "font" instead of "text" (e.g., $text_color is now $font-color).
• Colors for states such as hover and focus are now in the modifier suffix (e.g. $button-color--hover).
• Color variables are value agnostic because of themes. No use of "light" or "dark" concepts in vars.

• Removed repeated calculations with fractional vars
  • e.g. floor($cap-spacing / 2) can now use $cap-spacing--half
• Clarified var names for max/min heights based on either
  • internally defined by widget or panel panel-max-height--[size]
  • the height of the view (when a widget is inside a view) view-height--[size]__component-max-height

Animations have been moved to a separate file.